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In order to evaluate the chronic effect of polymerized toner particles on the lung, inflammation- and fibrosis-related genes were analyzed and 8-hydroxydeoxyguanosine (8-OHdG) was examined by using the lung tissue of rats subjected to 24 months of toner inhalation exposure. Wistar female rats were divided into four groups (5 weeks old, 30 rats in each): the high concentration exposure group (16.3 +/- 0.6 mg/m(3)), the medium concentration exposure group (4.4 +/- 0.3 mg/m(3)), the low concentration exposure group (1.6 +/- 0.2 mg/m(3)), and the control group (clean air). The material used was black toner, and its aerodynamic diameter in the exposure chamber was 3.0 microm. The rats were exposed to the material for 24 months (6 hours/day, 5 days/week) and dissected after the exposure period. RNA was extracted from one lung and the gene expression related to inflammation and fibrosis. Matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2), and type I collagen were analyzed according to the ratio of each gene/beta-actin. Also, 8-OHdG level in the lung tissue was measured by HPLC with an electrochemical detector. Small fibrotic foci were found in the toner exposed groups; however, progressive or irreversible fibrosis was not found. The incidence of small fibrotic foci and cell aggregation increased in a dose-dependent manner. There were no significant differences of expression of MMP-2, TIMP-2, and type I collagen between the control group and each exposed group. Lung tumors did not develop in each group. A significant production of 8-OHdG was not observed in the toner exposed groups. In conclusion, toner produced by polymerization was not associated with evidence of carcinogenesis in this experiment.

Superoxide dismutases (SODs) are antioxidant enzymes that catalyze the dismutation of superoxide into hydrogen peroxide. There are 3 kinds of isozymes: extracellular superoxide dismutase (EC-SOD), manganese-containing superoxide dismutase (Mn-SOD) and copper- and zinc-containing superoxide dismutase (CuZn-SOD). To examine the expression of SOD isozymes in lungs injured by crystalline silica, we intratracheally instilled male Wistar rats with 2 mg (8 mg/kg) of crystalline silica and investigated the mRNA, protein level and distribution of SOD isozymes in the rat lungs using RT-PCR, western blot analysis and immunostaining, respectively at from 3 d to 180 d of recovery following the exposure. EC-SOD mRNA levels significantly increased from 3 d to 90 d and the EC-SOD protein level was significantly higher after 90 and 180 d recovery in the crystalline silica exposed groups than in the control groups. Mn-SOD increased in silica treated rat lungs at both mRNA and protein levels, peaking at 30 d post-exposure. CuZn-SOD mRNA levels were decreased at 3, 7 and 30 d, and CuZn-SOD protein levels were also significantly lower than the control group at 90 and 180 d recovery. There was prominent EC-SOD immunostaining mainly in the plasma and alveolar macrophages and strong Mn-SOD staining in alveolar macrophages and interstitial cells of the proximal and distal portions of the alveolar duct following crystalline silica exposure. There was less CuZn-SOD staining in epithelial cells at terminal bronchioles in the crystalline silica-exposed group. These findings suggest that these SOD isozymes may be related to lung injury induced by crystalline silica.

Oxidative stress is thought to be the pathogenesis of pulmonary fibrosis induced by asbestos, and heme oxygenase-1 (HO-1) protects lung tissue against oxidative stress. We hypothesized that HO-1 is also associated with oxidative lung injury caused by exposure to chrysotile asbestos. This study was conducted to investigate the HO-1 expression of lungs in lung injury by chrysotile asbestos in vivo and in vitro. Male Wistar rats were administered 1 mg or 2 mg chrysotile suspended in saline by a single intratracheal instillation and were sacrificed at 3 days, 1 wk, 1 mo, 3 mo, and 6 mo of recovery time. The expression of HO-1 was observed by Western blot analysis, reverse-transcription polymerase chain reaction, and immunostaining. Protein levels of HO-1 increased at from 3 days to 6 mo following intratracheal instillation of 1 or 2 mg chrysotile. The mRNA levels of HO-1 increased at 3 mo and 6 mo following intratracheal instillation of 1 or 2 mg chrysotile. HO-1-positive cells were mainly found in the alveolar macrophages during immunostaining. We then examined HO-1 protein expression in human alveolar epithelial cells (A549). A549 cells were incubated with chrysotile at concentrations of 0, 12.5, 25, 50, and 100 microg/ml over 24 h. Increased expression of HO-1 protein was found following exposure to 25 or 50 microg/ml of chrysotile. Increased expression of HO-1 was also found at 6, 12, 24, and 48 h after exposure to 50 microg/ml of chrysotile with a peak at 24 h. These findings suggest that HO-1 is related to lung injury arising from exposure to chrysotile asbestos in vivo and in vitro.

Calcitonin gene-related peptide (CGRP), which has a function as a growth factor of epithelial cells, is thought to play a role in pulmonary epithelium repair. In order to establish whether or not CGRP is associated with repair in lung damaged by dust, we examined gene expression of CGRP in the lungs of animal models exposed to different dusts. Male Wistar rats were administered 2 mg of crystalline silica, crocidolite, potassium octatitanate whisker (PT-1), and silicon carbide whisker (SiCW) suspended in saline by a single intratracheal instillation and were sacrificed at 3 d, 1 wk, 1 mo, 3 mo, and 6 mo of recovery time. Pathological findings of advanced pulmonary fibrosis were present in the rats exposed to crystalline silica and crocidolite through the experiment, whereas findings of mild or reversible pulmonary fibrosis were present in those exposed to SiCW and PT-1. The expression of CGRP in rat lung was observed by reverse-transcription polymerase chain reaction (RT-PCR) and enzyme immunometric assay (EIA). In RT-PCR, CGRP gene expression was decreased at the interval of 3 d and 1 wk in the case of crystalline silica and crocidolite; on the other hand, it was increased at 3 d and 1 wk in SiCW and at 3 d, 1 wk, and 3 mo in PT-1-exposed rats. CGRP protein level in lungs exposed to PT-1 and SiCW was also higher than that to silica and crocidolite at 3 d of recovery time. These data suggest that CGRP is associated with repair in lung damaged by different dusts, and that CGRP could be used as a sensitive biomarker to indicate the pathogenicity of dusts.

A reduction of the biological half life of toluene in blood in the simultaneous exposure to toluene and alcohol vapors has been reported. To clarify the cause of this reduction, gene expression of CYP mRNA in liver of rats exposed to bi-component organic vapors was investigated. Wistar male rats were repeatedly exposed to 500 ppm of toluene and 300 ppm of 1-butanol vapors individually and simultaneously by inhalation 6 hours a day, five days a week for 4 weeks. After the exposure, the rats were sacrificed and the livers were collected and homogenized. RNA was extracted from the livers, and gene expression of CYP mRNA was observed by reverse transcription-polymerase chain reaction (RT-PCR). The gene expression of CYP3A2 in the simultaneous exposure group was significantly higher than that in the toluene exposure group. However, there was no significant difference in that of CYP1A2, CYP2B1, CYP2C11, CYP2E1 and CYP4A1.

Pulmonary surfactant comprised primarily of phospholipids is a phospholipid-protein complex synthesized by type II alveolar epithelial cells or Clara cells and secreted to the pulmonary alveoli. As changes have been found in phospholipid concentrations in the bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis, phospholipid is considered to be involved in the process of fibrois/fibrotic process. Therefore, we made a crystalline silica rat model and measured phospholipid concentrations in lung lavage fluid in order to study the relationship of phospholipid to particle-induced pulmonary fibrosis. Eight-week-old Wistar male rats (n = 35) were injected with 2 mg crystalline silica particles suspended in 0.4 ml physiological saline. Rats in the control group (n = 35) were injected with physiological saline only. There were 7 rats in each of the ten subgroups. Rats were sacrificed and dissected at 3 days, 1 wk, 1 mo, 3 mo, and 6 mo after injection. Bronchoalveolar lavage was conducted on bronchoalveoli recovered from the right lung of each rat, the lavage fluid was centrifuged, and the supernatant was used to measure phospholipid concentration. The results were compared with previously reported inflammation scores. Phospholipid concentrations in lung lavage fluid for the exposed group showed a statistically significant increase compared to the control group throughout the observation period. Moreover, when compared to histopathologically examined inflammation scores, a positive correlation was found between the two. Judging from the facts that phospholipid concentrations in lung lavage fluid increased and that this increase correlated with the severity of inflammation, this experiment indicated that phospholipids are involved in particle-induced lung disorders.

Oxidative stress is thought to be the pathogenesis of pulmonary fibrosis induced by particles, and heme oxygenase-1 (HO-1) protects lung tissue against oxidative stress. We hypothesized that HO-1 is also associated with oxidative lung injury caused by exposure to particles. The present study was conducted to investigate the time course of HO-1 expression of lungs exposed to crystalline silica in vivo. Male Wistar rats were administered 1 mg or 2 mg of crystalline silica suspended in saline by a single intratracheal instillation and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months of recovery time. The expression of HO-1 was observed by western blot analysis and immunostaining. Protein levels of HO-1 were increased compared to the controls at 3 d, and from 1 month to 6 months following intratracheal instillation of 2 mg of crystalline silica. The levels of HO-1 were increased compared to the controls from 1 month to 6 months following intratracheal instillation of 1 mg of crystalline silica. Many HO-1 positive cells were found particularly in the alveolar macrophages during immunostaining. These findings suggest that HO-1 is related to lung injury arising from exposure to crystalline silica.

We assessed the effects of long-term inhalation of toner on the pathological changes and formation of 8-hydroxydeoxyguanosine (8-OH-Gua) in DNA in a rat model. Female Wistar rats (10 wk old) were divided evenly into a high concentration exposure group (H: 15.2 mg/m(3)), a low concentration exposure group (L: 5.5 mg/m(3)), and a control group. The mass median aerodynamic diameter of the toner was 4.5 microm. The rats were sacrificed at the termination of a 1-yr or 2-yr inhalation period. Pathological examination was performed on the left lung, and the level of 8-OH-Gua in DNA from the right lung was measured using a high-performance liquid chromatography (HPLC) column. The pathological findings showed that lung cancer was not observed in any of the exposed or control groups, though pleural thickening and small foci of collagen were observed in toner-exposed rat lungs. Inhalation of the toner for 1 and even 2 yr did not induce the formation of 8-OH-Gua in DNA in rat lungs. These data suggest that long-term inhalation of toner may not induce lung tumors.

It has been theorized that Clara cell secretion protein (CCSP) plays a critical role in regulating the acute inflammatory response in the lung. We hypothesized that CCSP is also related to lung injury induced by occupational dust. The present study was conducted to investigate the time course of the expression of CCSP in lungs exposed to crystalline silica in vivo. Male Wistar rats were administered 1 mg or 2 mg of silica suspended in saline by a single intratracheal instillation and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months of recovery time. The expression of CCSP was observed by RT-PCR and western blot analysis. Exposure to 2 mg of silica decreased in levels of CCSP mRNA at 3 d, 1 wk, 1 month and 6 months following intratracheal instillation. The protein level of CCSP in silica-exposed rats was decreased at 3 d, 7 d and 1 month after a single instillation of 2 mg. The decreases in CCSP at the acute phase in this experiment suggest that CCSP may regulate the acute injury of the lung exposed to silica.

Oxidative stress is thought to be the pathogenesis of pulmonary fibrosis induced by asbestos, and heme oxygenase-1 (HO-1) protects lung tissue against oxidative stress. We hypothesized that HO-1 is associated with oxidative lung injury caused by exposure to asbestos. This study was conducted to investigate the time course of HO-1 expression of lungs exposed to crocidolite asbestos in vivo. Male Wistar rats were administered 1 mg or 2 mg crocidolite asbestos suspended in saline by a single intratracheal instillation and were sacrificed at 3 d, 1 wk, 1 mo, 3 mo, and 6 mo of recovery time. The expression of HO-1 was observed by Western blot analysis and immunostaining. Protein levels of HO-1 increased at from 3 d to 6 mo following intratracheal instillation of 2 mg crocidolite asbestos. The levels of HO-1 increased at 1 wk and 1 mo following intratracheal instillation of 1 mg crocidolite asbestos. Many HO-1-positive cells were found, particularly in the alveolar macrophages, during immunostaining. These findings suggest that HO-1 may be related to lung disorder induced by dust and therefore can act as a biomarker of lung injury due to dust exposure.

We assessed the effects of long-term inhalation of toner on the pathological changes and gene expression with the synthesis and degradation of collagenous extracellular matrix in a rat model. Female Wistar rats (10 wk old) were divided evenly into a high concentration exposure group (H: 15.2 mg/m3), a low concentration exposure group (L: 5.5 mg/m3), and a control group. The mass median aerodynamic diameter of toner was 4.5 microm. The rats were sacrificed at the termination of a 1-yr or 2-yr inhalation period. Pathological examination was performed from the left lung, and transcriptional levels of mRNA extracted from the right lung were assessed by semiquantitative reverse-transcription polymerase chain polymerase (RT-PCR). The pathological findings showed mild pulmonary fibrosis in 20% (L, 1 yr), 40% (H, 1 yr), 56% (L, 2 yr) and 62% (H, 2 yr), while lung cancer was not observed in any of the exposed groups. In the 1-yr high-concentration group, gene expression of matrix metalloproteinase-2 (MMP-2) and type I collagen mRNA in the rat lungs increased, while tissue inhibitors of metalloproteinase-2 (TIMP-2) decreased. The 2-yr high-concentration group increased in message level of type I collagen and TIMP-2 but not that of MMP-2. These data suggested that results of gene expression of MMP, TIMP, and collagen in the 2-yr exposure may lead to accumulation of collagen compared to the 1-yr exposure, and that the imbalance of the expression of MMPs, TIMPs, and extracellular matrix might be associated with pulmonary fibrosis induced by toner.

Intratracheal instillation studies have shown that exposure to silicon carbide whiskers (SiCW), an asbestos substitute, produces pulmonary fibrotic changes, suggesting that SiCW might have fibrogenic potential. It has been theorized that Clara cell secretory protein (CCSP) plays a critical role in regulating the acute inflammatory response in the lung. The present study was conducted to investigate the time course of the expression of CCSP in lungs exposed to SiCW in vivo. Male Wistar rats were administered 2 mg or 10 mg of SiCW suspended in saline by a single intratracheal instillation and were sacrificed at 3 days, 1 week, 1 month, 3 months and 6 months of recovery time. The expression of CCSP was observed by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot and immunostaining. Exposure to 10 mg of SiCW decreased in levels of CCSP mRNA at 3 days, 1 week, 1 month and 6 months following intratracheal instillation. The protein level of CCSP in SiCW-exposed rats was decreased at 1 day, 3 days and 1 month after a single instillation of 2 and 10 mg. These findings suggest that CCSP are involved not only in the acute injury but also in the chronic injury of the lung exposed to SiCW.

Intratracheal instillation studies have shown that exposure to silicon carbide whisker (SiCW), an asbestos substitute, produces pulmonary fibrotic changes, suggesting that SICW might have a fibrogenic potential. It is thought that surfactant protein is a good biomarker of lung injury and pulmonary fibrotic activity. In order to explore whether or not surfactant protein is associated with lung disorder through exposure to SiCW, we examined the expression of SP-A, SP-C and thyroid transcription factor-1 (TTF-1), a common transcription factor of SP-A and SP-C mRNA in lungs exposed to SiCW. Male Wistar rats were administered 2 mg or 10 mg of SiCW suspended in saline by a single intratracheal instillation, and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months after the intratracheal instillation. RNA was subsequently extracted from the lungs, and expression of SP-A, SP-C and TTF-1 mRNA from the lungs was observed by reverse transcription-polymerase chain reaction (RT-PCR). Exposure to 2 mg of SiCW showed a decrease in mRNA of SP-A and TTF-1 at 6 months, but exposure to 10 mg of SiCW showed decreased levels of SP-A and TTF-1 mRNA at 3 d and 6 months. On the other hand, 2 mg of SiCW increased the level of SP-C mRNA from 3 d to 3 months, and 10 mg of SiCW decreased the levels of SP-C mRNA in the rat lungs at 3 d, 1 month and 6 months. No clear tendency to the expression of SP-C was observed, but the patterns of expression of TTF-1 and SP-A were similar. These data suggest that SP-A and TTF-1 are associated with not only the acute phase but also the chronic phase in lungs exposed to SiCW.

1. We investigated the mechanism by which human interferon-alpha (IFN-alpha) increases the immobility time in a forced swimming test, an animal model of depression. 2. Central administration of IFN-alpha (0.05 - 50 IU per mouse, i.cist.) increased the immobility time in the forced swimming test in mice in a dose-dependent manner. 3. Neither IFN-beta nor -gamma possessed any effect under the same experimental conditions. 4. Pre-treatment with an opioid receptor antagonist, naloxone (1 mg kg(-1), s.c.) inhibited the prolonged immobility time induced by IFN-alpha (60 KIU kg(-1), i.v. or 50 IU per mouse. i.cist. ). 5. Peripheral administration of naloxone methiodide (1 mg kg(-1), s. c.), which does not pass the blood - brain barrier, failed to block the effect of IFN-alpha, while intracisternal administration of naloxone methiodide (1 nmol per mouse) completely blocked. 6. The effect of IFN-alpha was inhibited by a mu(1)-specific opioid receptor antagonist, naloxonazine (35 mg kg(-1), s.c.) and a mu(1)/mu(2) receptor antagonist, beta-FNA (40 mg kg(-1), s.c.). A selective delta-opioid receptor antagonist, naltrindole (3 mg kg(-1), s.c.) and a kappa-opioid receptor antagonist, nor-binaltorphimine (20 mg kg(-1), s.c.), both failed to inhibit the increasing effect of IFN-alpha. 7. These results suggest that the activator of the central opioid receptors of the mu(1)-subtype might be related to the prolonged immobility time of IFN-alpha, but delta and kappa-opioid receptors most likely are not involved.

To determine which parameters are useful for the risk assessment of man-made mineral fibers (MMMFs), we examined the gene expression of interleukin-1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6) and inducible nitric-oxide synthase (iNOS) in mineral fiber-exposed alveolar macrophages (AMs). Male Wistar rats were intratracheally exposed to saline or mineral fibers suspended in saline (2 mg of crocidolite, chrysotile, alumina silicate refractory fiber (RF1) or potassium octatitanate whisker (TW)). Bronchoalveolar lavage was performed 4 weeks after the fiber-instillation, and the recovered AMs were stimulated by lipopolysaccharide for 2 or 6 hours. Expression of IL-1 alpha, TNF alpha, IL-6 and iNOS from AMs was observed using reverse transcription-polymerase chain reaction (RT-PCR). The levels of IL-1 alpha and IL-6 mRNA induced by mineral fiber exposure were greatest in AMs exposed to TW, crocidolite, chrysotile and RF1 in that order. However, both gene expression of iNOS and TNF alpha were not elevated in both crocidolite and TW exposure, despite their high pathological potential. These data suggested that IL-1 alpha and IL-6 may be useful indicators for the risk assessment of MMMFs.

Irinotecan hydrochloride (CPT-11), an antitumor camptothecin derivative, causes severe forms of diarrhea clinically. We characterized CPT-11-induced diarrhea histologically and enzymologically and assessed the relationships between intestinal toxicity and the activity of the enzymes that play a key role in the major metabolic pathway of CPT-11 in rats. CPT-11 (60 mg/kg i.v. for 4 days) induced intestinal toxicity characterized by severe chronic diarrhea, loss of body weight, and anorexia. Histological damage was most severe in the cecum. The segmental difference in the degree of the damage showed good correlation with the beta-glucuronidase activity in the contents of the lumen in each case, but not with the intestinal tissue carboxylesterase activity, which converts CPT-11 to its active form (7-ethyl-10-hydroxycamptothecin). Inhibition of the beta-glucuronidase activity in the intestinal microflora by antibiotics (1 mg penicillin and 2 mg streptomycin per ml of drinking water) markedly ameliorated the diarrhea and reduced cecal damage. Analysis of CPT-11 and its metabolites in the feces indicated that antibiotics completely inhibited the deconjugation of the glucuronic conjugate of 7-ethyl-10-hydroxycamptothecin by beta-glucuronidase. It is suggested that CPT-11-induced diarrhea would be attributable to the damage to the cecum, and that the inhibition of the beta-glucuronidase activity in the intestinal microflora is a major protective effect of antibiotics.

We examined the combined effect of radiation and BOF-A2, a newly developed anti-cancer agent consisting of a masked form of 5-fluorouracil (5-FU) and a potent inhibitor of 5-FU degradation in the liver, on murine tumors. Subcutaneous 8-mm-diameter SCCVII tumours grown in the right thigh of C3H/He mice were used. The mice were locally irradiated with single doses of 10-30 Gy or five fractions of 4 Gy for 5 days, alone or in combination with BOF-A2. BOF-A2 at doses of 30, 75 and 150 mg kg-1 was orally administered 2 h before or immediately after single doses of irradiation, while 15 or 30 mg kg-1 of BOF-A2 was given 1 h prior to each fraction of 4 Gy. The effect of BOF-A2 alone was also examined. The antitumour effect was evaluated by a tumour growth delay assay. BOF-A2 alone showed significant tumour growth delay at all doses used in this study. Combination of BOF-A2 and single or fractionated doses of radiation appeared to produce an additive tumour response, which occurred independently of sequence of the two treatments. The combined effect became greater with the dose of radiation and BOF-A2. In conclusion, BOF-A2 and radiation may be efficiently combined.

In clinical use, irinotecan hydrochloride (CPT-11; 7-ethyl-10-[4-(piperidino)-1-piperidino]carbonyloxycamptothecin), a novel antitumor agent, causes a relatively high incidence of severe forms of diarrhea. We investigated whether baicalin, an inhibitor of beta-glucuronidase, which deconjugates the glucuronide of the active metabolite of CPT-11, SN-38 (7-ethyl-10-hydorxycamptothecin), and Japanese herbal medicines (Kampo medicines) which contain baicalin can ameliorate CPT-11-induced intestinal toxicity in rats. CPT-11 (60 mg/kg i.v. once daily for 4 consecutive days) induced intestinal toxicity characterized by diarrhea, loss of body weight, anorexia and disruption of intestinal epithelium. Treatment with baicalin (25 mg/kg p.o. twice daily) or Kampo medicines (TJ-14 and TJ-114; 1 g/kg p.o. twice daily) from the day before to 4 or 10 days after the start of CPT-11 administration resulted in significantly decreased weight loss, improved anorexia and delayed onset of diarrheal symptoms. Histological examination revealed that Kampo medicine-treated animals had less damage to the intestinal epithelium and that damage was repaired more rapidly than in control rats. These results suggest that the prophylactic use of Kampo medicines (TJ-14 and TJ-114) may be of value against CPT-11-induced intestinal toxicity.

The general pharmacological study of iodixanol, a non-ionic isotonic contrast medium, was conducted. 1) Iodixanol administered intravenously over a dose range of 320 to 3,200 mgI/kg had little or no effect on the general behavior, spontaneous locomotor activity, hexobarbital sleeping time, pain response, electroshock- or pentylenetetrazol-induced convulsion (mouse), EEG or body temperature (rabbit), gastrointestinal propulsion (mouse) or skeletal muscle contraction (rabbit). Iodixanol had no specific interaction with acetylcholine, histamine, serotonin, nicotin, BaCl2 (ileum), methacholine (trachea), isoprenaline (atrium) or oxytocin (pregnant uterus), nor had any effect on spontaneous contractility (atrium and uterus), or transmural electrostimulation-induced contractility (vas deferens) at concentrations of < or = 3.2 x 10(-3) gI/ml in vitro. Iodixanol had no effect on the cardiovascular system of dog, except that it increased femoral blood flow and respiratory rate at doses of > or = 1,000 mgI/kg. Iodixanol at 3,200 mgI/kg i.v. reduced urine output with a decrease in Na+ and Cl- excretion, whereas at 320 mgI/kg i.v., it slightly increased urine output (rat). 2) Injections of iodixanol into the cerebroventricular (0.96, 9.6 mgI/mouse and 3.2, 32 mgI/rat), left ventricular (1,920, 6,400 mgI/dog) or coronary artery (640, 1,920 mgI/dog) had no conspicuous effect on the central nervous system or the cardiovascular system, respectively. There was no marked difference among iodixanol, iohexol and iopamidol in this respect. Vascular pain during injection into the femoral artery (300-320 mgI/guinea pig) appeared to be less intense with iodixanol, compared with the other contrast media iohexol and iopamidol. These results suggest that intravenous injection of iodixanol is relatively free from pharmacological activity, and effects of iodixanol on the central nervous system (intracerebroventricular injection) and cardiovascular system (intra-left ventricular and -coronary injections) are comparable to those of iohexol and iopamidol. Furthermore, intra-femoral injection of iodixanol has less of a tendency to produce vascular pain than those of iohexol and iopamidol.

We investigated the mechanisms of CPT-11-induced diarrhea. 1) CPT-11 (80 mg/kg, i.v.) induced watery diarrhea within 1 hr after dosing in saline-loaded (10 ml/kg, p.o.) rats. This was partially inhibited by subcutaneous injection of atropine (1 mg/kg) or ondansetron (1 mg/kg) and almost completely inhibited by a combination of atropine and ondansetron or by clonidine (0.3 mg/kg) or morphine (10 mg/kg) alone. 2) CPT-11 at the same dose reduced intestinal fluid absorption, which was blocked by the anti-diarrheal agents mentioned above. Intraluminal injection of CPT-11 (20 mg/2 ml) inhibited fluid absorption and induced fluid secretion. 3) CPT-11, 60 mg/kg, by single intravenous injection induced fewer enzymological and histological changes in the small intestine than 5-FU at 270 mg/kg, while 4 consecutive dosings of CPT-11 induced delayed diarrhea (days 5-7) associated with disruption of intestinal integrity. Co-administration with anti-diarrheal agents, except for ondansetron, protected against watery diarrhea appearing within 1 hr after CPT-11 on days 3 and 4, but worsened delayed diarrhea. These results suggest that single injection of higher doses of CPT-11 causes watery diarrhea at an acute phase at least partly by reducing fluid absorption or increasing secretion, and that while conventional anti-diarrheal agents protect against watery diarrhea, their co-administration in repeated CPT-11 administration has no ameliorative effect on CPT-11-induced delayed diarrhea.

An approach to minimization of toxicity of a new compound is to elucidate the mechanisms of toxicity of analogous compounds and to clarify their structure-toxicity relationships. A problem with this approach, however, is that such elucidation remains difficult. For quinolones, some improvements in this mechanistic approach have been achieved in the central nervous system (CNS), particularly with regard to their interaction with non-steroidal anti-inflammatory drugs (NSAIDs), and in genotoxicity and phototoxicity studies, particularly in comparison with other toxicities, such as to the cardiovascular, gastrointestinal, bone, reproductive, and developmental systems. This review concentrates on a description of the known effects of quinolones on various organ systems in experimental animals and humans. Given the logarithmic increase in the synthesis of new quinolones, it is questionable whether these drugs share similar safety and efficacy. Nevertheless, this mechanistic approach to the investigation and minimization of toxicity has produced satisfactory results to date and deserves to be continued.

The general pharmacological properties of a novel cognition-enhancing agent, nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)acetamide, DM-9384, CAS 77191-36-7) were investigated, and the following results were obtained. 1. Central nervous system: Nefiracetam showed depressant activities (such as ataxia) on general behavior (mice), and inhibited spontaneous locomotor activity, rota-rod and traction performances (mice) and polysynaptic potential of the spinal reflex (rats), and potentiated pentobarbital anesthesia (mice). The drug inhibited electroshock-induced seizure at relatively low doses, but did not affect chemoshock-induced seizure (mice). Nefiracetam failed to show analgesic activity in the tail pinch test, but inhibited the acetic acid-induced writhing syndrome (mice). An inhibitory pattern in the electroencephalogram was observed (cats). Nefiracetam had little or no effect on body temperature (rats). 2. Respiratory and cardiovascular systems: Nefiracetam induced transient decreases in blood pressure, left ventricular pressure and LV dp/dt max at higher doses (dogs). 3. Autonomic nervous system: Nefiracetam had no influence on pupil size (rabbits). The drug induced no significant effect on the pressor response to norepinephrine or depressor response to acetylcholine, but inhibited the contractile response of the nictitating membrane to preganglionic cervical sympathetic nerve stimulation at the highest dose (dogs). 4. Gastrointestinal system: Nefiracetam inhibited gastrointestinal propulsion (mice), gastric emptying rate and gastric secretion (rats) at higher doses. Nefiracetam produced no apparent damage in the gastric mucosa, and had no effect on bile secretion (rats). 5. Isolated smooth muscle: Nefiracetam had no effect on the resting tonus of isolated ileum, whereas it inhibited the contractile response to acetylcholine, histamine, serotonin, nicotine and BaCl2 at higher concentrations (guinea pigs). Nefiracetam had no effect on the resting tonus or the serotonin-induced contraction of stomach fundus (rats). The drug had no effect on the resting tonus or the norepinephrine-induced contraction of vas deferens, but tended to inhibit the contraction induced by nerve stimulation (guinea pigs). Nefiracetam had little or no effect on the resting tonus or oxytocin-induced contraction of virgin uterus, or on spontaneous contraction of pregnant uterus (rats). Nefiracetam did not affect the resting tonus of trachea, whereas it inhibited isoproterenol-induced relaxation at the highest concentration (guinea pigs). Nefiracetam had no chronotropic effect in isolated atria, but showed a slight negative inotropic effect at the highest concentration (guinea pigs). 6. Miscellaneous: Nefiracetam slightly decreased urinary volume, whereas it did not affect urinary electrolyte excretion (rats).(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacological properties of the anti-ulcer drug 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl] methyl]-amino-N-methylbenzamide (DQ-2511, CAS 104775-36-2) on the central and autonomic nervous systems, smooth muscle, gastrointestinal system, and other miscellaneous systems were investigated. 1. DQ-2511 showed little or no influence on general behavior, spontaneous motor activity, hexobarbital sleeping time (mouse), conditioned avoidance response (rat), body temperature (rabbit), EEG or spinal reflex (cat) after oral administration (300-1000 mg/kg) or intravenous injection (15, 50 mg/kg). It also had no anticonvulsant or analgesic activities (mouse). 2. DQ-2511 had no influence on pupil size (rabbit). It reduced or tended to reduce contractile responses of the nictitating membrane induced by electrical stimulation of pre- and post-ganglionic sympathetic nerve (cat) at the highest dose. The drug inhibited the pressor response to norepinephrine, but had little or no inhibitory effect on the depressor response to acetylcholine at the highest dose (dog). 3. DQ-2511 reduced contractile responses to nicotine, BaCl2, acetylcholine, histamine and serotonin (isolated guinea pig ileum), to acetylcholine and histamine (trachea), and to norepinephrine (vas deferens) at high concentrations. It also inhibited spontaneous and oxytocin-induced motility (isolated rat uterus). 4. DQ-2511 decreased gastric motility in a dose-related manner at intravenous doses of 5-50 mg/kg (dog). It also reduced gastric emptying rate at oral doses of 100-1000 mg/kg, and gastric secretion at intraperitoneal doses of 100-300 mg/kg (rat). On the other hand, it induced no definite changes in intestinal motility (dog) or gastrointestinal transit (mouse).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular activities of 3-[[[2-(3,4-dimethoxyphenyl)ethyl]carbamoyl]methyl]-amino-N- methylbenzamide (DQ-2511, CAS 104775-36-2), an anti-ulcer drug, were investigated in anesthetized dogs and conscious rats. In anesthetized and laparotomized dogs, DQ-2511 at intravenous doses of 5-50 mg/kg dose-relatedly induced an increase in celiac and mesenteric arterial blood flow, and a decrease in their resistance, whereas the drug had little or no effect on carotid and renal blood flow. DQ-2511 increased cardiac contractility in anesthetized dogs at an intravenous dose of 15 mg/kg. In addition to this effect, it produced an increase in respiratory rate, a decrease in blood pressure and a slight increase in heart rate after dosing at 50 mg/kg. The drug had little or no effect on femoral blood flow and produced no significant changes in the electrocardiogram. In conscious rats, blood flow in gastrointestinal organs was compared with flow in other organs using the microsphere method. Blood flow in the stomach, duodenum, ileum, pancreas, spleen, and kidney tended to decrease in the vehicle-treated control group. DQ-2511, at an oral dose of 100 mg/kg, significantly increased blood flow in the stomach, duodenum and spleen, and tended to increase flow in the pancreas, testis and fat in comparison with the vehicle-treated control group. Blood flow in the liver, heart and skeletal muscle tended to decrease, whereas the other regional blood flows did not differ from those in the control group. DQ-2511 at this oral dose had little or no effect on blood pressure, heart rate, cardiac output and total peripheral resistance in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

The general pharmacological properties of (-)-(S)-9-fluoro-2,3-dihydro-3- methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de][1,4] benzoxazine-6-carboxylic acid hemihydrate (levofloxacin, DR-3355, CAS 100986-85-4), an optically active isomer of ofloxacin, were examined. 1. Central nervous system (CNS): DR-3355 at 200-600 mg/kg p.o. showed depressant activity on the CNS, as was indicated by the depressant syndrome (mice), decreased spontaneous motor activity (mice) and hypothermia (mice and rabbits). In the cat behavior and EEG experiments, it had both stimulant and depressant effects at 30-100 mg/kg i.p., and caused transient slow waves followed by seizures at 20-30 mg/kg i.v. DR-3355 had no effect on convulsion, hexobarbital anesthesia, pain reaction to a tail pinch, or conditioned avoidance response, except that it showed mild analgesic activity in acetic acid writhing at 600 mg/kg p.o. 2. Respiratory and cardiovascular system: DR-3355 produced a hypotensive and a bradycardiac effect after the rapid i.v. injection of 6 mg/kg or more in anesthetized dogs, accompanied by an increase in plasma histamine concentration. Both changes were markedly reduced when the test drug was administered by continuous i.v. infusion. 3. Autonomic nervous system: DR-3355 inhibited nictitating membrane contraction induced by both pre- and post-ganglionic stimulation, and inhibited the depressor response to acetylcholine at 20 mg/kg i.v. It had no influence on pupil size or on pressor response to norepinephrine. 4. Gastrointestinal system: DR-3355 at 600 mg/kg p.o. inhibited gastric secretion. Dog gastrointestinal motility was slightly inhibited, and was then stimulated over the dose range of 2-20 mg/kg i.v. It had no influence on gastrointestinal propulsion, the gastric emptying rate or the gastric mucosa. 5. Isolated smooth muscle: At a concentration of 5 x 10(-4) g/ml, DR-3355 was devoid of spasmogenic or smasmolytic activity, except for showing a slight relaxation effect (trachea), inhibition of nicotine-induced contraction (ileum) and spontaneous or oxytocin-induced motility (pregnant uterus). 6. Miscellaneous: DR-3355 inhibited the urine output and carrageenin-induced paw edema at 600 mg/kg p.o. It had no effect on skeletal muscle contraction or the corneal reflex.

Pharmacological properties of midaglizole (DG-5128, CAS 66529-17-7) on smooth muscle, gastrointestinal and miscellaneous systems were investigated in comparison with those of tolbutamide. 1. Isolated smooth muscle: Midaglizole inhibited the contractile responses of the ileum to nicotine, acetylcholine, serotonin and BaCl2, and especially the response to histamine (guinea pig). Tolbutamide also reduced the contractions. On spontaneous motility of the uterus (estrus, diestrus, pregnant), midaglizole produced an increase in tonus and frequency, and decrease in contractile amplitude (rat). Tolbutamide reduced the motility of the uterus. The contractile response of the vas deferens to norepinephrine was potentiated after midaglizole and tolbutamide (guinea pig). Midaglizole inhibited the contractile response of the trachea to histamine, whereas it had little or no effect on the response to acetylcholine (guinea pig). Tolbutamide reduced the responses to both spasmogens. 2. Gastrointestinal system: Midaglizole induced an increase in gastrointestinal transit (mouse) and potentiated the gastrointestinal motility (dog). Tolbutamide was without any effect on these parameters. Gastric emptying rate, gastric secretion and gastric mucosa were not influenced after midaglizole (rat). Tolbutamide decreased gastric secretion and produced injury of gastric mucosa. 3. Urine volume: Midaglizole and tolbutamide showed a diuretic activity (rat). 4. Anti-inflammatory activity: Midaglizole and tolbutamide inhibited carrageenin-induced paw edema (rat).

Respiratory and cardiovascular effects of midaglizole (DG-5128, CAS 66529-17-7) were investigated in comparison with yohimbine, idazoxan and tolbutamide. 1. Respiration: Midaglizole had little or no effect on respiration of anesthetized dogs. Yohimbine and idazoxan augmented respiration at low dose. Tolbutamide depressed respiratory rate and depth at high dose. 2. Blood pressure and heart rate: Midaglizole produced dose-related hypotension and bradycardia in anesthetized dogs which had laparotomy, whereas it had little or no effect on blood pressure and heart rate of dogs which had no laparotomy (unlaparotomized dogs). Tendency of slight hypertension was observed after high dose of tolbutamide in laparotomized dogs, and transient hypotension was induced in unlaparotomized dogs. Yohimbine and idazoxan increased blood pressure at low dose in unlaparotomized dogs. In laparotomized dogs, yohimbine produced hypertension and hypotension at low and high doses, respectively. In isolated guinea pig atria, midaglizole produced bradycardia which was not observed after yohimbine. Tolbutamide decreased the pulse rate at high concentration. 3. Cardiac contractility: Midaglizole produced increase in cardiac contractility of anesthetized dogs. Yohimbine and idazoxan, at low dose, showed similar inotropic activity. Prazosin also produced a positive inotropic effect, whereas tolbutamide lacked the activity. The inotropic effects of midaglizole and yohimbine were antagonized by pretreatment with propranolol or hexamethonium, whereas a similar effect of prazosin was not influenced by both blockers. In isolated guinea pig atria, midaglizole showed slight inotropic activity. Yohimbine was without any effect, whereas tolbutamide reduced the contractile force. 4. Femoral blood flow: Midaglizole produced a transient increase in femoral blood flow and a decrease in femoral arterial resistance of anesthetized dogs. Yohimbine and idazoxan, at low dose, showed similar vasodilator activity. Prazosin also produced a vasodilator effect, whereas tolbutamide lacked the activity. The vasodilator effects of midaglizole and yohimbine were not affected with propranolol, but inhibited after hexamethonium. 5. Mesenteric blood flow: Midaglizole significantly decreased mesenteric blood flow and increased the arterial resistance of anesthetized dogs in a dose dependent manner. Tolbutamide induced a decrease in blood flow and an increase in arterial resistance only at the highest dose used. Yohimbine increased mesenteric blood flow at low dose and decreased it at high dose. 6. Renal blood flow: Midaglizole dose-relatedly decreased renal blood flow of anesthetized dogs. Tolbutamide and yohimbine at high dose produced a long-lasting decrease of the blood flow. Midaglizole produced a slight transient reduction of renal arterial resistance which was followed by a slight increase. Tolbutamide increased the arterial resistance at high dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacological properties of midaglizole (DG-5128, CAS 66529-17-7) on central and peripheral nervous systems were investigated in comparison with those of tolbutamide. 1. Central nervous system: Midaglizole showed little or no effects on general behavior (mouse), spontaneous motor activity (mouse), hexobarbital anesthesia (mouse), conditioned avoidance response (rat) and body temperature (rabbit) at an oral dose of 100 mg/kg. It also produced little or no changes in electroencephalogram (cat) and spinal reflex (cat) after intravenous dosing of 10 mg/kg. The drug lacked anticonvulsant and analgesic activities (mouse). Midaglizole produced clonic convulsion, mydriasis, lacrimation, increase in pinna reflex, decrease in spontaneous motor activity, increase in pain threshold (mouse) and rise in body temperature (rabbit) at oral dose of 300 mg/kg. Tolbutamide showed similar effects except that it potentiated hexobarbital anesthesia, slightly decreased convulsion and tended to decrease body temperature. 2. Autonomic nervous system: Midaglizole potentiated the pressor response to norepinephrine and inhibited the depressor response to acetylcholine at an intravenous dose of 10 mg/kg (anesthetized dogs). Similar results were observed after dosing of tolbutamide. Midaglizole potentiated the contractile response of nictitating membrane to pre- and post-ganglionic cervical sympathetic nerve stimulation after intravenous dosing of 1 mg/kg (cat). Tolbutamide lacked the activity on the contraction elicited by both stimulations. Midaglizole and tolbutamide had little or no effect on pupil size (rabbit). 3. Skeletal muscle contraction (neuromuscular junction): Midaglizole (3-10 mg/kg i.v.) slightly potentiated the tibialis anterior muscle contraction induced by peroneal nerve stimulation, but did not potentiate the contraction by direct (muscle) stimulation (rabbit). On the other hand, tolbutamide increased the contraction induced by both nerve and muscle stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Midaglizole (3 and 30 mg/kg, i.v.) increased blood pressure in pithed rats. The pressor response was not inhibited by intravenous prazosin (0.3 mg/kg), yohimbine (1 mg/kg), ketanserin (1 mg/kg) or diphenhydramine (5 mg/kg). Diltiazem (1 mg/kg) antagonized the hypertension. Idazoxan (10 mg/kg) also increased blood pressure, and the pressor response was inhibited by prazosin, but not by yohimbine. These results suggest that the vascular effect of midaglizole is due to a mechanism different from that of idazoxan.

The alpha 2-adrenoceptor antagonistic potency of midaglizole was evaluated and compared with that of the selective alpha 2-adrenoceptor antagonists yohimbine and idazoxan. Intravenously administered midaglizole, like yohimbine and idazoxan, reversed the clonidine-induced inhibition of the tachycardic response to cardiac nerve stimulation in pithed rats. Midaglizole, yohimbine and idazoxan inhibited the pressor responses to B-HT 920 (alpha 2-adrenoceptor agonist), in a dose-related manner, to a greater extent than the response to methoxamine (alpha 1-adrenoceptor agonist). Conversely, prazosin produced a highly selective antagonism of the methoxamine-evoked response in this preparation. Midaglizole failed to antagonize centrally mediated hypotension and bradycardia induced by intravenous clonidine, whereas the other alpha 2-antagonists attenuated the clonidine-induced cardiovascular responses in intact rats. These results suggest that midaglizole is a selective alpha 2-adrenoceptor antagonist and, unlike yohimbine and idazoxan, is characterized by its ability to block peripheral but not central alpha 2-adrenoreceptors when administered systemically.

General pharmacological properties of carvedilol (BM 14.190) were investigated in comparison with propranolol. 1. Central nervous system: Carvedilol caused reduction of awareness, motor activity and muscle tone, and staggering gait in Irwin's test (mice). It decreased spontaneous motor activity and potentiated hexobarbital anesthesia (mice). It lacked anticonvulsant activity (mice) and did not have any effect on body temperature (rabbits). Various changes were produced in mono- and polysynaptic spinal reflex (cats). In EEG, a slight arousal pattern was observed (cats). These effects of carvedilol were weaker than those observed after propranolol administration in general. Carvedilol, however, caused potentiation of hexobarbital anesthesia at lower doses than propranolol. Carvedilol inhibited acetic acid-induced writhing syndrome, whereas it failed to show analgesic activity in the tail-pinch test (mice). Propranolol inhibited both pain reactions. 2. Respiratory and cardiovascular system (dogs): Carvedilol increased respiratory rate and decreased expiratory velocity. It produced hypotension and bradycardia. Cardiac contractility was reduced and femoral blood flow was transiently increased after carvedilol administration. Propranolol induced weaker hypotension and greater bradycardia in comparison with carvedilol. It decreased femoral blood flow. 3. Autonomic nervous system: Carvedilol had little or no effects on pupil size, whereas propranolol produced mydriasis (rabbits). Carvedilol inhibited pressor response to norepinephrine (rats), and it also reduced the nictitating membrane contraction induced by pre- and postganglionic sympathetic nerve stimulation (cats). Propranolol did not show any inhibitory effect on pressor response to norepinephrine and on the contractile response induced by preganglionic sympathetic nerve stimulation. 4. Smooth muscle: Carvedilol produced inhibitory effects on spontaneous motility, and contractile responses to acetylcholine, histamine, nicotine, serotonin and BaCl2 in isolated ileum (guinea pigs). It also inhibited contractile responses to acetylcholine and histamine in isolated trachea (guinea pigs), and spontaneous motility in isolated uterus (rats). Carvedilol reduced norepinephrine-induced contraction of isolated vas deferens at lower concentration (guinea pigs). 5. Digestive system: Decrease in intestinal motility was observed after intravenous administration of carvedilol and propranolol (rabbits). However, carvedilol failed to influence on gastric motility and tonus, whereas propranolol increased them (rabbits). Carvedilol, like propranolol, induced little or no effects on gastro-intestinal transit (mice) and gastric emptying rate (rats). Both drugs decreased gastric secretion at similar dose (rats). Carvedilol at higher doses produced lesion of gastric mucosa, whereas propranolol did not show these effects (rats). 6. Skeletal muscle: In in vitro experiment, carvedilol, like propranolol, reduced the contractile response of diaphragm to nerve and muscle stimulation (rats)...

General pharmacological properties of 4'-fluoro-4-[4-(2-thioxo-1-benzimidazolinyl) piperidino] butyrophenone (timiperone), a new neuroleptic drug, were compared with those of haloperidol. 1. Central nervous system: In behavioral observation, timiperone showed a typical neuroleptic profile at doses of 0.1 mg/kg p.o. and more (mice). The drug produced a moderate hypothermia at 10 mg/kg p.o. (rabbits), a mild increase in pain threshold at 3 mg/kg p.o. (mice and rats) and a slowing of cortical EEG at 1 mg/kg i.v. (cats). ED50 values of drug for the potentiation of ether and alcohol anesthesia were 0.34 and 0.22 mg/kg p.o., respectively (mice). Timiperone ahd neither an anticonvulsant activity at 30 mg/kg p.o. (mice) nor an effect on the spinal reflex at 1 mg/kg i.v. (cats). These effects of timiperone on the central nervous system were almost similar to those of haloperidol. 2. Respiratory and cardiovascular system: At dose of 0.03 mg/kg i.v. and more, timiperone produced transient increases in respiratory rate and regional arterial blood flow which were accompanied by a fall in blood pressure (dogs). Haloperidol had qualitatively similar effect, but was weaker than timiperone. Both drugs at high concentration (3X10-6 g/ml) exerted negative inotropic and chronotropic effect in isolated atrial preparations (guinea-pigs), and non-competitively antagonized the positive chronotropic action of isoprenaline. Atropine (2.5X10-7 g/ml) failed to modify the chronotropic action of timiperone (3X10-6 g/ml). 3. Autonomic nervous system: Timiperone at 0.1 mg/kg p.o. and haloperidol at 0.3 mg/kg p.o. induced a moderate miosis (rabbits) and antagonized blood responses to noradrenaline and acetylcholine (dogs). Both drugs at 1 mg/kg i.v. had no ganglion-blocking activity (cats). 4. Smooth muscle: In isolated guinea-pig ileum and vas deferens, timiperone and haloperidol (10-5 g/ml) antagonized the contractile responses of the muscles to various spasmogens, Both drugs at approximately 10-6 g/ml decreased spontaneous motility of the isolated rat uterus and inhibited the gastric secretion at 1 mg/kg i.p. (rats). At high doses, both drugs inhibited the gastrointestinal propulsion (mice), motility (dogs) and gastric emptying rate (rats), and had no damaging effect on the gastric mucosa (rats). 5. Skeletal muscle: At 0.1 mg/kg i.v., timiperone and haloperidol slightly enhanced twitch response of the anterior tibial muscle to electrical stimulation (rabbits). 6. Urine volume and urinary electrolytes: Timiperone and haloperidol showed a diuretic effect at 3 mg/kg p.o. whereas they inhibited urine output and electrolytes excretion at 30 mg/kg p.o. (rats).

Antihypertensive and general pharmacological properties of 1-[2-(1,3-dimethyl-2-butenylidene)hydrazino]phthalazine (budralazine) were studied in comparison with those of hydralazine. Single oral administration of budralazine (4--15 mg/kg) to DOCA/saline hypertensive rats resulted in a dose-related and sustained antihypertensive effect which was 2--3 times less potent than that of hydralazine. However, there were no remarkable differences between both drugs in the hypotensive magnitude after the 4-week treatment of spontaneously hypertensive rats (SHR) with their higher doses. After single oral administration, budralazine was about 8 times less potent than hydralazine in increasing plasma renin activity in normotensive rats. At effective antihypertensive doses, budralazine inhibited spontaneous motor activity (mice), gastrointestinal propulsion (mice), gastric emptying rate (rats), gastric secretion (rats), urine output and urinary electrolyte excretion (rats) as well as carrageenan-induced paw edema formation (rats), which were essentially less potent than those produced by hydralazine. Budralazine at 6 mg/kg i.v. exhibited a slowing of neocortical EEG (cats) and a slight increase in spinal monosynaptic potentials (cats) and inhibited gastrointestinal motility (dogs). The same dose of hydralazine produced an increase in occurrence of the neocortical fast waves, an inhibition of the monosynaptic potentials and the carotid sinus reflex (dogs) and a stimulation of intestinal motility followed by prolonged and marked reduction. Budralazine (10(-5) g/ml) slightly potentiated contractile response of isolated guinea-pig vas deferens to noradrenaline, whereas hydralazine (10(-4) g/ml) inhibited the response. Budralazine (10(-5) g/ml), like hydralazine (10(-4) g/ml), produced a nonspecific antagonism against the contractile response of isolated guinea-pig ileum to various spasmogens, and both drugs (10(-4) g/ml) reduced either spontaneous motility or oxytocin-induced motility in isolated rat uterus.

Cardiovascular effects of cinepazide were compared with those of cinnarizine and papaverine. Cinepazide (3-30 mg/kg, i.v.) produced a dose-related and transient increase in vertebral, carotid, renal and femoral arterial flow as well as cardiac output and a decrease in total peripheral resistance in anesthetized dogs. The magnitude and duration of mesenteric vasodilatation induced by cinepazide was much greater as compared to other vascular effects, and these effects were associated with a prolonged hypotension. The drug exerted positive inotropic and chronotropic actions, the latter being followed by bradycardia with the highest dose. Cinnarizine (0.3-3 mg/kg, i.v.) produced a greater increase in vertebral blood flow with bradycardia and papaverine (0.1-1 mg/kg, i.v.) produced a remarkable carotid vasodilatation with cardiac stimulation. Both reference drugs decreased renal blood flow. Cinepazide (30 mg/kg, i.v.) potentiated the vertebral vasodilator response of dogs to intravertebral adenosine and cyclic AMP, while cinnarizine (3 mg/kg i.v.) reduced their vasodilator effects. Intravertebral cinepazide(1-10 mg), like cinnarizine (0.1-1 mg) and papaverine (0.1-1 mg), increased vertebral blood flow in a dose-related manner and the effect was partially inhibited by intravenous pretreatment with aminophylline but not by pretreatment with autonomic antagonists. These antagonists did not modify the cinnarizine effect. Cinepazide resembled cinnarizine and papaverine in that the drug antagonized rabbit aortic contraction induced by KCl, norepinephrine or CaCl2.

Intravenous injection of 1-[2-(1,3-dimethyl-2-butenylidene)hydrazino]phthalazine (budralazine) to anesthetized dogs resulted in an increase in cardiac output and regional blood flow in various vascular beds, and a fall in mean blood pressure with a decreased total and regional vascular resistance. Budralazine produced a dose-related increase in femoral blood flow in anesthetized dogs when injected into the femoral artery. The vasodilator drug relaxed either KCl(K+)- or noradrenaline (NA)-induced contractions of isolated rabbit aorta in a concentration-dependent manner. In the K+-depolarized aorta, it also produced a concentration-related inhibition of contractile response to cumulative addition of Ca2+. Intra-arterial injection of budralazine dilated dose-dependently the isolated perfused vascular bed of rabbit ear constricted by either K+ or NA. Budralazine, at effective antihypertensive oral dose, was without significant effect on cyclic nucleotide levels in the aorta of spontaneously hypertensive rats (SHR). These results indicate that budralazine, like hydralazine, produces vasodilation through a direct effect on vascular smooth muscle which may result at least in part from its inhibitory effect on vascular Ca2+ fluxes.

Effects of cinepazide, a vasoactive agent, on regional circulations in various sites of brain and other organs in curarized, artificially respirated cats were studied using a thermoelectrical method. The mechanism of the vascular effect was also investigated. Cinepazide produced a marked increase in blood flow in the cerebellar cortex and an apparent increase in blood flow in the cerebral cortex. Effects of the drug on blood flow in the thalamus, hypothalamus and amygdala were inconsistent. Cinepazide produced the most significant increase in myocardial blood flow and also an apparent increase in muscular blood flow, whereas the drug did not consistently alter hepatic blood flow, and decreased renal and dermal blood flow. Cinepazide produced a mild and sustained fall in blood pressure, however, a transient slight rise in blood pressure was noted when the drug was given into the vertebral artery. It seems possible that the action of cinepazide might involve a mild stimulation of beta adrenergic receptors and slight stimulation of alpha adrenergic receptors but not cholinergic receptors, in the cerebral and peripheral vascular systems. Increase in blood flow induced by cinepazide seems to be mainly due to the smooth muscle relaxant effect and may be mediated via a metabolic mechanism.

General pharmacological effects of N2-[(N-acetyl-muramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-ly sine MDP-Lys(L18), muroctasin) were examined and the following results were obtained. 1. Central nervous system: MDP-Lys(L18) had no effect on behavior, spontaneous motor activity, electroshock- and chemoshock-induced convulsions, hexobarbital sleeping time, pain threshold (mice), conditioned avoidance response (rats) at a dose of 0.4 mg/kg, s.c. and EEG as well as spinal reflex (cats) at a dose of 0.4 mg/kg, i.v. It produced a significant elevation in body temperature (rabbits) at doses of 13 micrograms/kg, s.c. and greater. 2. Respiratory and cardiovascular system (dogs): MDP-Lys(L18) did not show any significant effect on respiratory and cardiovascular functions at a dose of 0.4 mg/kg i.v. 3. Autonomic nervous system: MDP-Lys(L18) induced a miosis (rabbits) at doses of 13 micrograms/kg s.c. and greater. It did not affect norepinephrine-induced pressor and acetylcholine-induced depressor responses (dogs) and contraction of the nictitating membrane induced by electrical stimulation (cats) at a dose of 0.4 mg/kg i.v. 4. Smooth muscles: In the experiments using the isolated ileum, vas deferens, trachea (guinea pigs) and uterus (rats), MDP-Lys(L18) showed neither spasmogenic nor spasmolytic activity at a concentration of 4 x 10(-6) g/ml. Gastrointestinal propulsion (mice), gastric mucosa, gastric emptying rate and gastric secretion (rats) were not affected by this drug at a dose of 0.4 mg/kg s.c. MDP-Lys(L18) did not influence gastrointestinal motility (dogs) at a dose of 0.4 mg/kg, i.v. 5. Miscellaneous: MDP(L-18) suppressed carrageenan-induced edema (rats) at doses of 0.13 mg/kg s.c. and greater.(ABSTRACT TRUNCATED AT 250 WORDS)

Budralazine was evaluated for its protective effect on the onset of cerebrovascular lesions in SHR given 1.5% NaCl as drinking water. The salt-loading for 67 days rapidly accelerated the development of hypertension in SHR (from 180 to over 250 mmHg, 40 days after the loading). The acceleration of hypertension was accompanied by an increase in the incidence of brain softening, cerebral infarct, angionecrosis and hemorrhage by 30-60% following the thrombosis and necrosis of cerebral arterioles. Renal angionecrosis associated with the interstitial nephrosis was also observed by 90% in the animals. Throughout the salt-loading period, oral administration of budralazine (1, 4 and 15 mg/kg/day) resulted in a dose-dependent inhibition of the accelerated hypertension. At larger doses (4 and 15 mg/kg/day), budralazine almost completely ameliorated the cerebral and renal lesions and significantly attenuated the rise of weight in the brain and heart observed in the salt-loaded control rats. Changes in the serum biochemical findings were also inhibited by this drug. In some of the parameters measured, budralazine appeared to be more efficacious than hydralazine (1, 4 and 15 mg/kg/day, p.o.). These results suggest that budralazine attenuates the serious development of hypertension and reduces the incidence and severity of stroke in salt-loaded SHR.

Sensitive and specific radioimmunoassay for substance P was developed using synthetic substance P and 125I-Nalpha-tyrosyl-substance P. Substance P-human alpha-globulin conjugate was used for production of anti-substance P antisera in rabbits. Synthetic substance P was used as a standard and the dextran-coated charcoal method was employed to separate the free peptide from that bound to antibodies. No cross-reactions by physalaemin and eledoisin observed in this system proved its high specificity to substance P. Nalpha-Tyrosyl-substance P and [Tyr1]-substance P showed the displacement curves indistinguishable from that of the standard substance P. Neither substance P5-11 nor substance P6-11 competed with the tracer at the concentration used. The minimum measurable dose of substance P by the assay system was 2.5-5 pg/incubate. Utilizing the system, human plasma samples from 42 healthy volunteers of both sexes were shown to contain immunoreactive substance P in amounts that averaged 298 pg/ml in male and 251 pg/ml in female. Substance P-like immunoreactivity was also demonstrated in hot-water extracts of porcine duodenum, jejunum, ileum, cecum, middle colon, rectum, pancreas, stomach and pituitary. The highest concentration (379 ng/g wet weight of organ) was found in the pituitary, and the ileum (7.9 ng/g wet weight of organ) and jejunum (1.9 ng/g wet weight of organ) were rich in the contents.