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The involvement of spinal glial cells in the nociceptive behaviors induced by 1600 pmol of histamine was determined in mice. Histamine injected intrathecally (i.t.) produced nociceptive behaviors, consisting of scratching, biting and licking. The nociceptive behaviors induced by histamine were significantly suppressed by i.t. pretreatment with the glial cell inhibitor DL-fluorocitric acid or minocycline. In Western blot analysis using lumber spinal cords, i.t. treatment with histamine increased the phosphorylation of the NR1 subunit of N-methyl-D-aspartate (NMDA) receptors. The increased phosphorylation of the NR1 subunit of NMDA receptors by histamine was abolished by i.t. pretreatment with DL-fluorocitric acid or minocycline. We have previously reported that the nociceptive behaviors induced by 1600 pmol of histamine were significantly suppressed by the i.t. co-administration of (5R,10 S)-(+)-5-methyl-10,11-dihydro-5 H-dibenzo[a,d]cycloheptene-5,10-imine (MK-801), an ion channel blocker of NMDA receptors, or agmatine, an antagonist for the polyamine recognition site on the NR1 subunit of NMDA receptors. In the present study, the increased phosphorylation of the NR1 subunit of NMDA receptors by histamine was also abolished by i.t. co-administration of agmatine or MK-801. The present results suggest that histamine at 1600 pmol elicits nociceptive behaviors by stimulating the polyamine recognition site on the NR1 subunit of NMDA receptors on spinal glial cells.

It has been reported that chlorpheniramine, a classical antihistamine, has antidepressant-like effects in animal models of depression. In this study, we examined the involvement of dopaminergic (dopamine D(1) and dopamine D(2) receptors), noradrenergic (alpha(1)- and beta-adrenoceptors) and serotonergic (5-HT(1A) and 5-HT(2) receptors) receptors in the antidepressant-like effect of chlorpheniramine in the mouse tail suspension test. We also investigated the involvement of these monoamine receptors in the antidepressant-like effect of imipramine for comparison with the mechanisms of the effect of chlorpheniramine. Both imipramine and chlorpheniramine significantly reduced the duration of immobility in the tail suspension test without affecting spontaneous locomotor activity in mice. The anti-immobility effect of imipramine (30 mg/kg, i.p.) was significantly antagonized by the selective dopamine D(1) receptor antagonist SCH23390 but not by the other receptor antagonists. In contrast, the anti-immobility effect of chlorpheniramine was significantly inhibited by SCH23390 and the selective alpha(1)-adrenoceptor antagonist prazosin, but not by the other receptor antagonists. In conclusion, these results suggest that chlorpheniramine exerts an antidepressant-like effect in the mouse tail suspension test that is mediated by at least the activation of dopamine D(1) receptors and alpha(1)-adrenoceptors. In addition, the antidepressant-like effect of chlorpheniramine may be induced by several mechanisms that are different from those involved in the antidepressant-like effect of imipramine.

The 3′ end of a primer is a key component of PCR primer design. Many recommendations for the composition and sequence of the 3′ end have been suggested based on theoretical considerations, but have not been verified experimentally. We analyzed 3′ end triplets of PCR primer sequences obtained from refereed journal articles, to test those recommendations and to make empirical recommendations for primer design. The frequencies of the 64 possible 3′end triplets among 2137 PCR primers from the VirOligo database were not uniformly distributed. From the analysis, we found that unfavored and preferred 3′ end triplets existed, and that the apparent preferences were not due to base compositions in viral genome sequences. Comparison of the sequences preferred by practitioners to those recommended, suggested that no single recommendation is entirely satisfactory. We suggest that recommendations be replaced with a scoring system incorporating empirical frequencies such as those reported here.

Objectives We report a sensitive and selective method for the simultaneous determination of vitamin K1 and K2 analogs (VKs) with high-performance liquid chromatography in which a platinum catalyst reduction column and an electrochemical detector operated in the oxidation mode are incorporated into the detection system. We also applied this trace analysis method to the simultaneous determination of VKs in human serum to investigate the physiologic and pathophysiologic roles of VKs in the bone metabolism. Methods Our high-performance liquid chromatographic method with postcolumn catalyst reduction and electrochemical detection was applied for the simultaneous determination of VKs in human serum samples. After separation of VKs on a reversed-phase separation column by using a mixture of ethanol and methanol (1:1, v/v), containing 0.025 M of sodium perchlorate as the mobile phase, the VKs were reduced once in a platinum catalyst reduction column connected online and then monitored quantitatively by an electrochemical detector with a glassy carbon working electrode operated in the oxidation mode (+0.6 V versus Ag/AgCl). Results VKs were clearly separated from each other within 80 min. The detection limits at a signal-to-noise ratio of 3 were 2 to 10 pg for VKs. Quantitative recovery from serum was obtained in the range of 86% to 91% for VKs. The average coefficients of variation of within-day and between-day assays were 1.6% to 2.1% and 2.4% to 3.6%, respectively, for all VKs. Conclusions This method was sensitive and selective for detection of VKs and was satisfactory in the simultaneous determination of VKs in small volumes of human serum.

Objective: We investigated the effects of phenytoin, an antiepileptic drug, and vitamin K2 (menatetrenone) on bone mineral density and the changes in the levels of menaquinone derivatives (MK-1 ∼ MK-14) in the sera and femurs of growing male rats. Methods: Levels of menaquinone derivatives were measured with high-performance liquid chromatography with an electrochemical detector. Results: Bone mineral density values decreased significantly in all parts of the femoral bones measured (diaphysis and metaphysis) in the phenytoin-treated group. When the serum and bone levels of menatetrenone and MK-6 decreased due to phenytoin administration, we observed bone loss in rats. Conversely, when bone loss was prevented by the combined administration of phenytoin and menatetrenone, serum and bone levels of menatetrenone and MK-6 increased to the levels of vehicle-treated rats. Conclusions: Long-term phenytoin exposure may inhibit bone formation concomitantly with insufficient vitamin K, which, at least in part, contributes to bone loss in rats.

Intrathecal injection of histamine elicited a behavioral response consisting of scratching, biting and licking in conscious mice. Here, we have examined the involvement of substance P (SP) by using intrathecal injection of tachykinin neurokinin (NK)(1) receptor antagonists and SP antiserum. Histamine-induced behavioral response was evoked significantly 5-10 min after intrathecal injection and reached a maximum at 10-15 min. Dose-dependency of the induced response showed a bell-shaped pattern from 200 to 3200 pmol, and maximum effect was observed at 800-1000 pmol. The H(1) receptor antagonist, d-chlorpheniramine and pyrilamine but not the H(2) receptor antagonists, ranitidine and zolantidine, inhibited histamine-induced behavioral response. The NK(1) receptor antagonists, CP-99,994, RP-67580 and sendide, inhibited histamine-induced behavioral response in a dose-dependent manner. A significant antagonistic effect of [D-Phe(7), D-His(9)]SP (6-11), a selective antagonist for SP receptors, was observed against histamine-induced response. The NK(2) receptor antagonist, MEN-10376, had no effect on the response elicited by histamine. Pretreatment with SP antiserum resulted in a significant reduction of the response to histamine. No significant reduction of histamine-induced response was detected in mice pretreated with NK A antiserum. The present results suggest that elicitation of scratching, biting and licking behavior induced by intrathecal injection of histamine may be largely mediated by NK(1) receptors via H(1) receptors in the spinal cord.

The antinociceptive effects of pinacidil, an adenosine triphosphate (ATP)-sensitive K(+)i (K(ATP)) channel opener, were examined using the tail-flick test in non-diabetic and diabetic mice. Pinacidil i.c.v. produced dose-dependent antinociception in both non-diabetic and diabetic mice. There was no significant difference between the antinociceptive effect of i.c.v. pinacidil in non-diabetic mice and diabetic mice. The i.t. administration of pinacidil also produced dose-dependent antinociception in both non-diabetic and diabetic mice, however, the antinociceptive effect of i.t. pinacidil in diabetic mice was significantly greater than that in non-diabetic mice. The antinociceptive effect of i.c.v. or i.t. pinacidil was significantly antagonized by i.c.v. or i.t. glibenclamide, a K(ATP) channel blocker in both non-diabetic and diabetic mice. In non-diabetic mice, the antinociceptive effect of i.c.v. or i.t. administration of pinacidil was significantly antagonized by beta-funaltrexamine, a mu-opioid receptor antagonist, 7-benzylidenenaltrexone, a delta1-opioid receptor antagonist, naltriben, a delta2-opioid receptor antagonist, and nor-binaltorphimine, a kappa-opioid receptor antagonist. In diabetic mice, the antinociceptive effect of i.c.v. pinacidil was significantly reduced by 7-benzylidenenaltrexone, naltriben, and nor-binaltorphimine. However, beta-funaltrexamine had no effect on antinociception induced by i.c.v. pinacidil in diabetic mice. On the other hand, the antinociceptive effect of i.t. pinacidil was significantly antagonized by beta-funaltrexamine, 7-benzylidenenaltrexone, naltriben, and nor-binaltorphimine in diabetic mice. These results indicated that pinacidil produced antinociception through the release of opioid peptides acting at mu-, delta- and kappa-opioid receptors in surpraspinal and spinal cord of non-diabetic mice. On the other hand, in diabetic mice, the antinociception-induced by pinacidil was mediated through the release of opioid peptides acting at delta- and kappa-opioid receptors supraspinally, whereas pinacidil produced antinociception through the release of opioid peptides acting at mu-, delta-, and kappa-opioid receptors spinally.

In this study, we investigated 1) whether the administration of phenytoin induced bone loss; and 2) whether menatetrenone could prevent bone loss induced by phenytoin. For this purpose, we previously developed a procedure to measure the bone mineral density using a conventional X-ray absorptiometry method. A long-termed administration of phenytoin (20 mg/kg per day for 5 weeks) produced bone loss in the tibiae of growing rats. The values of bone mineral density (BMD) were significantly decreased in the tibial diaphysis and metaphysis in the phenytoin-treated group. In this period, we measured the serum level of vitamin K-dependent protein, osteocalcin, a marker of bone formation. The serum level of osteocalcin showed a decrease in the phenytoin-treated group compared with the vehicle-treated group. Combined administration of menatetrenone (30 mg/kg in diet per day) with phenytoin for 5 weeks prevented the reduction of BMD, and the level of osteocalcin was slightly increased. Thus, it is suggested that long-termed phenytoin exposure may inhibit bone formation concomitantly with insufficient vitamin K, which, at least in part, contributed to bone loss in rats. Finally, these findings implicated the therapeutic usefulness of menatetrenone on a moderate degree of bone abnormality such as drug-induced osteopenia.

Intrathecal (i.t.) injection of histamine elicited a significant hyperalgesic response as assayed by the tail-flick test. This hyperalgesic effect peaked at 15 min following i.t. administration of histamine (800 pmol) and returned to control level with 30 min. Hyperalgesia produced by histamine was inhibited dose-dependently by i.t. co-administration of the histamine H1 receptor antagonist, d-chlorpheniramine, but not the histamine H2 receptor antagonist, ranitidine. The tachykinin NK1 receptor antagonists, (+)-[(2S,3S)-3-(2-methoxy-benzyl-amino)-2-phenylpiperidine] (CP-99,994), and [Tyr6, d -Phe7, d -His9]substance P-(6–11) (sendide), inhibited histamine-induced hyperalgesic response in a dose-dependent manner. A significant antagonistic effect of [ d -Phe7, d -His9]substance P-(6–11), a selective antagonist for substance P receptors, was observed against histamine-induced hyperalgesic response. The tachykinin NK2 receptor antagonist, Asp-Tyr- d -Trp-Val- d -Trp- d -Trp-Lys-NH2 (MEN-10,376), had no effect on hyperalgesia elicited by histamine. The competitive N-methyl- d -aspartate (NMDA) receptor antagonists, and d -(−)-2-amino-5-phosphonovaleric acid ( d -APV), (±)-3-(2-carboxypiperazin-yl)propyl-1-phosphoric acid (CPP), the noncompetitive NMDA receptor antagonist dizocilpine (MK-801), and l -NG-nitro arginine methyl ester ( l -NAME), a nitric oxide (NO) synthase inhibitor, markedly inhibited histamine-induced hyperalgesic response. The present results suggest that hyperalgesic response induced by i.t. injection of histamine may be mediated by tachykinin NK1 receptors, but not NK2 receptors in the spinal cord. In addition, spinal NMDA receptor–NO system may also contribute to elicitation of hyperalgesia following i.t. injection of histamine.

We investigated whether inhaled pinacidil and moguisteine inhibit capsaicin-induced coughs in guinea pigs. Inhaled pinacidil (15 - 60 microg/ml), an ATP-sensitive K+ channel opener, and moguisteine (15 - 60 microg/ml) each dose-dependently inhibited the number of capsaicin-induced coughs. The antitussive effects of pinacidil and moguisteine were significantly antagonized by pretreatment with glibenclamide (10 mg/kg, i.p.), an ATP-sensitive K+ channel blocker. However, pretreatment with naloxone methiodide (10 mg/kg, s.c.) had no significant effect on the antitussive effects of either pinacidil or moguisteine. On the other hand, inhaled dihydrocodeine (15 - 60 microg/ml) also dose-dependently suppressed the number of capsaicin-induced coughs. The antitussive effect of inhaled dihydrocodeine was significantly antagonized by pretreatment with naloxone methiodide (10 mg/kg, s.c.), but not by glibenclamide (10 mg/kg, i.p.). These results indicate that inhaled pinacidil and moguisteine both attenuate capsaicin-induced coughs. Pinacidil and moguisteine may exert their antitussive effects through the activation of ATP-sensitive K+ channels in the tracheobronchial tract. Furthermore, it is possible that ATP-sensitive K+ channels may be involved in the antitussive effects of peripherally acting non-narcotic antitussive drugs.

We investigated the induction of metallothionein (MT) by cadmium (Cd) in the bone tissue of rats. To clarify the cell response to Cd in bone, the isoform-specific expression of MT mRNAs (MT-I and MT-II) was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Both MT-I and MT-II mRNA levels were increased within 3 h by Cd administration. MT (MT-I/MT-II) localization after single Cd injection were also confirmed by immunohistochemical studies. Notably, MT-positive cells were time-dependently increased, and the positive cells were mainly localized in osteocytes. The cell-specific induction of MT may be associated with Cd accumulation and Cd-induced bone injury in vivo. Furthermore, we also found that MT was consecutively expressed in some osteoclasts of control rats. This finding suggested a new role of osteoclasts in bone metabolism.

The antinociceptive effect of vitamin K2 (menatetrenone) in mice was examined using tail-flick and formalin test. Menatetrenone at doses of 10, 50 and 100 mg/kg, i.p. produced a dose-dependent and significant inhibition of the tail-flick response in mice. Menatetrenone (50 and 100 mg/kg, i.p.) had no significant effect on the duration of the first phase of the formalin-induced flinching. However, menatetrenone (100 mg/kg, i.p.) significantly inhibited the second phase of the formalin-induced flinching. I.p. administration of menatetrenone (100 mg/kg) significantly reduced the duration of nociceptive responses induced by i.t. injection of bradykinin, but not of substance P, prostaglandin E2 or N-methyl-D-aspartate (NMDA). These present data suggest that i.p. pretreatment with menatetrenone produced dose-dependent antinociceptive effect in mice. This effect may be, at least in part, mediated by the inhibition of bradykinin dependent nociceptive transmission in the spinal cord.

1. The purpose of this study was to compare the effect of NIK-247 on muscarinic receptor subtypes with that of tacrine (THA) in rats. 2. NIK-247 and tacrine dose dependently inhibited the binding of [3H]pirenzepine (M1), [3H]AF-DX 384 (M2), and [3H]4-DAMP (M3). The IC50 values for NIK-247 were 4.4 x 10(-6) M, 1.1 x 10(-5) M, and 1.5 x 10(-5) M, respectively, whereas those for tacrine were 5.8 x 10(-7) M, 2.0 x 10(-6) M, and 5.8 x 10(-6) M, respectively. 3. Gpp[NH]p, a GTP analogue, slightly shifted the curve of displacement of [3H]AF-DX. 384 binding for NIK-247 to the right. However, Gpp[NH]p did not shift the curve of displacement of [3H]pirenzepine and [3H]4-DAMP binding to the right. 4. NIK-247 moderately decreased the rate of beating in right atrial preparations, but did not decrease it below 50% of control level. 5. These findings indicate that NIK-247 is an M1 antagonist, M2 partial agonist, and M3 antagonist.

We studied the effect of therapeutic doses of theophylline on electrically-induced convulsions in developing mice. A theophylline dose as small as 3 mg/kg increased seizure susceptibility of 21-day-old mice, but not of 42-day-old mice. These findings were consistent with clinical reports that theophylline at the therapeutic blood concentrations occasionally induced convulsions in children. The age-dependent proconvulsant effect of theophylline was well inhibited by phenobarbital (PB), dose-dependently, but not by other well-established antiepileptic drugs (AEDs). PB may be a good choice of AED in patients with bronchial asthma and seizure disorders, if PB is indicative for their seizure types. The proconvulsant effect of theophylline in 21-day-old mice was counteracted by not only an adenosine A1 agonist, but also an NMDA antagonist and a histamine H3 antagonist. Several studies have established that the proconvulsant effect of theophylline intoxication is mainly due to the blockade of adenosine A1 receptors. The present findings suggested that the proconvulsant properties of therapeutic doses of theophylline in developing period were different from those of theophylline intoxication. Combination of therapeutic doses of theophylline and centrally-acting histamine H1 antagonists showed proconvulsant effects even in 42-day-old mice, suggesting that peripherally acting histamine H1 antagonists, such as astemizole, evastine and epinastine, were much safer than centrally acting histamine H1 antagonists for patients with both allergy and seizure history.

To examine biochemical changes in the brain histamine (HA) neuron system after acute and chronic administrations of methamphetamine (MAP), HA levels and histidine decarboxylase (HDC) activities in the rat cortex, striatum, diencephalon, midbrain, pons-medulla and cerebellum were measured. In the cortex and striatum, acute administration of MAP (1 and 3 mg/kg) increased HA levels 1 h later. Acute administration of MAP (10 mg/kg) and chronic administration of MAP (3 mg/kg) for 21 days also increased HA levels and HDC activities in the cortex and striatum I h after the last injection. In the diencephalon, acute administration of MAP (3 and 10 mg/kg) and chronic administration of MAP (3 mg/kg) decreased HA level 1 h after the last injection, but chronic administration of MAP (3 mg/kg) increased HDC activity 1 h after the last injection. There were no significant changes in HA levels and HDC activities in other regions after acute and chronic administrations of MAP. These findings suggest that MAP may activate the brain HA neuron system, although MAP acts more strongly on the cortex and striatum than on the diencephalon.

The effects of thioperamide, an H3 antagonist, and histamine H1 and H2 antagonists (s.c.) on morphine (s.c. or i.c.v.)- and U-50,488H (i.c.v.)-induced antinociception in male ddY mice were examined using the hot-plate (55 degrees C) test. Thioperamide significantly inhibited morphine-induced antinociception, but not U-50,488H-induced antinociception. The suppressive effect of thioperamide on morphine-induced antinociception was reversed by the H1 antagonist pyrilamine, but not by the H2 antagonist zolantidine. On the other hand, pyrilamine significantly potentiated the antinociception induced by morphine, but not that induced by U-50,488H. Zolantidine significantly inhibited morphine-induced antinociception in a dose-dependent manner, but not U-50,488H-induced antinociception. Both astemizole, an H1 antagonist, and ranitidine, an H2 antagonist, which are known to barely cross the blood brain barrier, did not affect morphine-induced antinociception. These results suggest that morphine-induced antinociception may be potentiated by activation of H2 receptors and suppressed by activation of H1 receptors in the brain. Furthermore, neuronal histamine release induced by thioperamide may suppress morphine-induced antinociception through H1 receptors.

We studied the effects of inactivators of the central histaminergic neuron system, (R)-alpha-methylhistamine, a histamine H3 receptor agonist, and (S)-alpha-fluoromethylhistidine, a histamine synthesis inhibitor, on locomotor activity and brain histamine content of mast cell-deficient W/Wv mice using a recently developed high-performance liquid chromatography system coupled with a fluorometric detector. IP injection of (R)-alpha-methylhistamine (6-50 mg/kg) increased brain histamine content after 1 h but caused no significant change in locomotor activity. IP injection of (S)-alpha-fluoromethylhistidine decreased brain histamine content at doses of 6-50 mg/kg and locomotor activity at doses of 12.5-50 mg/kg. However, locomotor activity was decreased significantly (in Student's t-test) by sequential administrations of (S)-alpha-fluoromethylhistidine (6 mg/kg) and (R)-alpha-methylhistamine (12.5 or 25 mg/kg), but not by (S)-alpha-fluoromethylhistidine (6 mg/kg) and other doses of (R)-alpha-methylhistamine (6 or 50 mg/kg). These results support the hypothesis that the central histaminergic neuron system is involved in the control of spontaneous locomotion or alertness.

The antinociceptive effect of vitamin K2 (menatetrenone) in diabetic mice was examined using a tail-pressure test. Intraperitoneal injection of menatetrenone (10-100 mg/kg) produced a dose-dependent increase in the nociceptive threshold in diabetic mice. There was no significant difference between non-diabetic and diabetic mice in the menatetrenone-induced changes in the nociceptive threshold. The results suggest the therapeutical usefulness of menatetrenone for treating painful diabetic neuropathy and osteoporosis.

Studies were made on the role of μ1-receptors on electrically induced convulsions in mice. A relatively selective μ1-agonist, DAGO ([ d -Ala 2 -N- methyl-Phe 4 - Gly-ol]-enkephalin ) decreased the durations of tonic and clonic convulsions in C57BL/6 mice, but not in opioid μ-deficient CXBK mice, indicating that the activation of μ1-rreceptors had an anticonvulsive effect on these convulsions in mice. The selective μ1-antagonists naloxonazine and naltrexonazine promoted the clonic phase of electrically induced convulsion in C57BL/6 mice. Moreover, the duration of the clonic phase was longer in μ-deficient CXBK mice than in C57BL/6 mice. These data for CXBK mice confirmed, at least some proconvulsant effects of μ1-antagonists in C57BL/6 mice. Thus, blockade of μ1-receptors has a proconvulsant effect, and μ1-receptors have at least some protective role against electrically induced convulsions.

We examined the effects of (S)-alpha -fluoromethylhistidine (FMH), an inhibitor of histidine decarboxylase, and metoprine, an inhibitor of histamine N-methyltransferase, on the locomotor activity and the brain histamine content of ICR mice. The brain histamine content was decreased by FMH (12.5 or 50 mg/kg, i.p.) and increased by metoprine (4 mg/kg, i.p.). Under these conditions, the locomotor activity and the number of rearing were significantly decreased and increased by FMH and metoprine, respectively. The higher the brain histamine content, the greater the locomotor activity and vice versa. In a previous paper [Sakai et al., Life Sciences, 48, 2397-2404 (1991)], we showed that thioperamide, a histamine H3 antagonist, which enhances the release of histamine from histaminergic neurons, in doses of 12.5 and 25 mg/kg, i.p. increases the locomotor activity, whereas it decreases the brain histamine content. Taken together, these results support the hypothesis that central histaminergic neurons may be involved in the control of state of locomotion and rearing.

The effects of phenytoin and its major metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH), on bone resorption of neonatal mouse calvaria were examined in vitro. Both phenytoin and HPPH induced significant bone resorption as compared to the controls after 72 h in culture. This effect may be the cause of phenytoin-induced bone loss in vivo.

The purpose of this study was to examine the effects of thioperamide, a histamine H3 antagonist, on the locomotor activity and the brain histamine content in mast-cell-deficient W/Wv mice. Thioperamide (12.5 and 25 mg/kg) showed significant increase in the locomotor activity of W/Wv mice, measured by a photo-beam system, 1 hr after the intraperitoneal injection. However, more than 75 mg/kg of thioperamide showed not only the reduction of the locomotor activity but also the inhibition of motor coordination measured by the rotarod performance. The increase in the locomotor activity by thioperamide was blocked by i. p. pretreatment with (R)-alpha-methyl-histamine, an H3 agonist, or pyrilamine, an H1 antagonist, or zolantidine, an H2 antagonist. The brain histamine content was decreased by thioperamide (12.5-75.0 mg/kg), 1 hr after administration. Thus, the blockade of histamine H3 receptor by thioperamide showed the activation of locomotor activity of mice, which may be mediated by H1 and/or H2 receptors. The present data support the hypothesis that central histaminergic neurons may be involved in the control of state of wakefulness.

The rats maintained on a thiamine-deficient diet for 30 days showed hypothermia, and their histamine levels increased significantly in both the anterior and posterior hypothalamus. When these rats were administered, thiamine disulfide and/or provided with thiamine-added diet for a further 30 days, the rats recovered from hypothermia, and histamine levels were decreased to the normal level. Thus, it is probable that the increased histamine levels in the hypothalamus, especially those in its anterior region, are closely related to the hypothermia in thiamine-deficient rats.

Long-term treatment with antiepileptics has been known to cause a variety of bone disorders. The present study was undertaken to investigate effects of long-term administration of three antiepileptic agents (phenytoin, zonisamide and valproate) on bone metabolism in growing rats. The results showed that all three agents decreased the bone mineral density in both metaphysis and diaphysis. The magnitude of the decrease was greater in the metaphysis than diaphysis for zonisamide, but it was not for phenytoin and valproic acid. The above results showed that phenytoin, zonisamide and valproic acid could induce bone loss in growing rats. These phenomena would have some influences on development and progress of oral diseases.