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Inducing carotid body anoxia through the administration of cyanide can result in oxygen deprivation. The lack of oxygen activates cellular responses in specific regions of the central nervous system, including the Nucleus Tractus Solitarius, hypothalamus, hippocampus, and amygdala, which are regulated by afferent pathways from chemosensitive receptors. These receptors are modulated by the brain-derived neurotrophic factor receptor TrkB. Oxygen deprivation can cause neuroinflammation in the brain regions that are activated by the afferent pathways from the chemosensitive carotid body. To investigate how microglia, a type of immune cell in the brain, respond to an anoxic environment resulting from the administration of NaCN, we studied the effects of blocking the TrkB receptor on this cell-type response. Male Wistar rats were anesthetized, and a dose of NaCN was injected into their carotid sinus to induce anoxia. Prior to the anoxic stimulus, the rats were given an intracerebroventricular (icv) infusion of either K252a, a TrkB receptor inhibitor, BDNF, or an artificial cerebrospinal fluid (aCSF). After the anoxic stimulus, the rats were perfused with paraformaldehyde, and their brains were processed for microglia immunohistochemistry. The results indicated that the anoxic stimulation caused an increase in the number of reactive microglial cells in the hypothalamic arcuate, basolateral amygdala, and dentate gyrus of the hippocampus. However, the infusion of the K252a TrkB receptor inhibitor prevented microglial activation in these regions.

The hippocampus is a brain region crucially involved in regulating stress responses and highly sensitive to environmental changes, with elevated proliferative and adaptive activity of neurons and glial cells. Despite the prevalence of environmental noise as a stressor, its effects on hippocampal cytoarchitecture remain largely unknown. In this study, we aimed to investigate the impact of acoustic stress on hippocampal proliferation and glial cytoarchitecture in adult male rats, using environmental noise as a stress model. After 21 days of noise exposure, our results showed abnormal cellular proliferation in the hippocampus, with an inverse effect on the proliferation ratios of astrocytes and microglia. Both cell lineages also displayed atrophic morphologies with fewer processes and lower densities in the noise-stressed animals. Our findings suggest that, stress not only affects neurogenesis and neuronal death in the hippocampus, but also the proliferation ratio, cell density, and morphology of glial cells, potentially triggering an inflammatory-like response that compromises their homeostatic and repair functions.

The c-fos gene was first described as a proto-oncogene responsible for the induction of bone tumors. A few decades ago, activation of the protein product c-fos was reported in the brain after seizures and other noxious stimuli. Since then, multiple studies have used c-fos as a brain activity marker. Although it has been attributed to neurons, growing evidence demonstrates that c-fos expression in the brain may also include glial cells. In this review, we collect data showing that glial cells also express this proto-oncogene. We present evidence demonstrating that at least astrocytes, oligodendrocytes, and microglia express this immediate early gene (IEG). Unlike neurons, whose expression changes used to be associated with depolarization, glial cells seem to express the c-fos proto-oncogene under the influence of proliferation, differentiation, growth, inflammation, repair, damage, plasticity, and other conditions. The collected evidence provides a complementary view of c-fos as an activity marker and urges the introduction of the glial cell perspective into brain activity studies. This glial cell view may provide additional information related to the brain microenvironment that is difficult to obtain from the isolated neuron paradigm. Thus, it is highly recommended that detection techniques are improved in order to better differentiate the phenotypes expressing c-fos in the brain and to elucidate the specific roles of c-fos expression in glial cells.

Prolonged or intense exposure to environmental noise (EN) has been associated with a number of changes in auditory organs as well as other brain structures. Notably, males and females have shown different susceptibilities to acoustic damage as well as different responses to environmental stressors. Rodent models have evidence of sex-specific changes in brain structures involved in noise and sound processing. As a common effect, experimental models have demonstrated that dendrite arborizations reconfigure in response to aversive conditions in several brain regions. Here, we examined the effect of chronic noise on dendritic reorganization and c-Fos expression patterns of both sexes. During 21 days male and female rats were exposed to a rats' audiogram-fitted adaptation of a noisy environment. Golgi-Cox and c-Fos staining were performed at auditory cortices (AC) and hippocampal regions. Sholl analysis and c-Fos counts were conducted for evidence of intersex differences. In addition, pro-BDNF serum levels were also measured. We found different patterns of c-Fos expression in hippocampus and AC. While in AC expression levels showed rapid and intense increases starting at 2 h, hippocampal areas showed slower rises that reached the highest levels at 21 days. Sholl analysis also evidenced regional differences in response to noise. Dendritic trees were reduced after 21 days in hippocampus but not in AC. Meanwhile, pro-BDNF levels augmented after EN exposure. In all analyzed variables, exposed males were the most affected. These findings suggest that noise may exert differential effects on male and female brains and that males could be more vulnerable to the chronic effects of noise.

Introduction: Noise is one of the main sources of discomfort in modern societies. It affects physiology, behavior, and cognition of exposed subjects. Although the effects of noise on cognition are well known, gender role in noise-cognition relationship remains controversial., Aim: We analyzed the effects of noise on the ability of male and female rats to execute the Radial Arm Water Maze (RAWM) paradigm., Materials and Methods: Male and female Wistar rats were exposed to noise for 3 weeks, and the cognitive effects were assessed at the end of the exposure. RAWM execution included a three-day training phase and a reversal-learning phase conducted on the fourth day. Escape latency, reference memory errors, and working memory errors were quantified and compared between exposed and non-exposed subjects., Results: We found that male rats were in general more affected by noise. Execution during the three-day learning phase evidenced that male exposed rats employed significantly more time to acquire the task than the non-exposed. On the other hand, the exposed females solved the paradigm in latencies similar to control rats. Both, males and females diminished their capacity to execute on the fourth day when re-learning abilities were tested., Conclusion: We conclude that male rats might be less tolerable to noise compared to female ones and that spatial learning may be a cognitive function comparably more vulnerable to noise., Competing Interests: None

The repeated injection of insulin (unconditioned stimulus, UCS) immediately followed by exposure to sensory stimulation (e.g. sound or odor; conditioned stimulus, CS) results in a learned conditioned reflex in which the exposure to the CS alone lowers blood glucose. The brain regions participating in this hypoglycemic Pavlovian response remain unknown. Here we investigate if nitric oxide (NO) in the nucleus tractus solitarius (NTS), a nucleus known to be involved in glucose homeostasis, participates in this hypoglycemic reflex. Insulin injections (UCS) were paired with exposure to menthol odor (CS). After 8-10 reinforcements (4-5days training), rats acquire the learned hypoglycemic response. An increase in c-Fos expression was observed in the NTS, the ventrolateral hypothalamic nucleus (VLH) and other brain regions of conditioned rats. Microinjections of 3-(5'-hydroxymethyl-2'furyl)-1-benzyl indazole (YC-1) a stimulator of soluble guanylate cyclase (sGC) into NTS before the UCS accelerated the acquisition of the learned hypoglycemic response; 5-6 reinforcement produced pronounced glucose drop when exposed to the CS. In contrast, an inhibitor of NO synthase (NOS) N ω -Nitro-l-arginine methyl ester (L-NAME) in the NTS prolonged the required training period (11-15 reinforcements) to obtain the hypoglycemic reflex, and reduced the glycemic response. The number of c-Fos expressing cells in the NTS and VLH in rats receiving YC-1was significantly higher than that observed in rats receiving L-NAME. These findings suggest that NO-cGMP-PKG signaling in the NTS can modify the acquisition of conditioned hypoglycemia, and suggests that this nucleus directly participates in this reflex., (Copyright © 2017. Published by Elsevier B.V.)

In this study, we exposed adult rats to chronic variable stress (CVS) and tested the hypothesis that previous early-life exposure to stress changes the manner in which older subjects respond to aversive conditions. To this end, we analyzed the cytogenic changes in the hippocampus and hippocampal-dependent spatial learning performance. The experiments were performed on 18-month-old male rats divided into four groups as follows: Control (old rats under standard laboratory conditions), Early-life stress (ELS; old rats who were exposed to environmental noise from postnatal days, PNDs 21-35), CVS + ELS (old rats exposed to a chronic stress protocol who were previously exposed to the early-life noise stress) and CVS (old rats who were exposed only to the chronic stress protocol). The Morris Water Maze (MWM) was employed to evaluate the spatial learning abilities of the rats at the end of the experiment. Immunohistochemistry against 5'Bromodeoxyuridine (BrdU) and glial fibrillar acidic protein (GFAP) was also conducted in the DG, CA1, CA2 and CA3 regions of the hippocampus. We confocally analyzed the cytogenic (BrdU-labeled cells) and astrogenic (BrdU + GFAP-labeled cells) changes produced by these conditions. Using this procedure, we found that stress diminished the total number of BrdU+ cells over the main proliferative area of the hippocampus (i.e., the dentate gyrus, DG) but increased the astrocyte phenotypes (GFAP + BrdU). The depleted BrdU+ cells were restored when the senile rats also experienced stress at the early stages of life. The MWM assessment demonstrated that stress also impairs the ability of the rats to learn the task. This impairment was not present when the stressful experience was preceded by the early-life exposure. Thus, our results support the idea that previous exposure to mild stressing agents may have beneficial effects on aged subjects.

In this experiment, we evaluated the long-term effects of noise by assessing both astrocyte changes in medial prefrontal cortex (mPFC) and mPFC-related alternation/discrimination tasks. Twenty-one-day-old male rats were exposed during a period of 15 days to a standardized rats' audiogram-fitted adaptation of a human noisy environment. We measured serum corticosterone (CORT) levels at the end of the exposure and periodically registered body weight gain. In order to evaluate the long-term effects of this exposure, we assessed the rats' performance on the T-maze apparatus 3 months later. Astrocyte numbers and proliferative changes in mPFC were also evaluated at this stage. We found that environmental noise (EN) exposure significantly increased serum CORT levels and negatively affected the body weight gain curve. Accordingly, enduring effects of noise were demonstrated on mPFC. The ability to solve alternation/discrimination tasks was reduced, as well as the number of astroglial cells. We also found reduced cytogenesis among the mPFC areas evaluated. Our results support the idea that early exposure to environmental stressors may have long-lasting consequences affecting complex cognitive processes. These results also suggest that glial changes may become an important element behind the cognitive and morphological alterations accompanying the PFC changes seen in some stress-related pathologies.

We have previously reported that dietary tryptophan (TRP) restriction in a rat crucial postnatal developmental stage induces depression-like behavior and alters dendritic spine density in CA1 pyramidal neurons and granule cells of the hippocampus. Due to astrocyte involvement in critical brain mechanisms, it seems worth to investigate possible adaptive changes in the glial population with TRP restriction. Experimental rats were fed with low TRP diet (20% of TRP level of the laboratory rat chow) from postnatal days 30-60. Antibody against glial fibrillary acidic protein (GFAP), a principal intermediate filament in astrocytes, was used to evaluate cytoskeletal hypertrophy and glial proliferation. Our results showed an increase in size and branching of GFAP-immunoreactive (IR) cells in the dorsal hippocampus and amygdala, characteristics of an astrocytic activation. No significant differences were found regarding the number of GFAP-IR cells in both regions. These results indicate that dietary TRP restriction can induce astrocytic activation, hence, provide further evidences supporting the hypothesis that serotonin may also modulate glial morphology.

Objective: The Mongolian gerbil is one of the main animal species used for the study of global ischemia, due to its specific Circle of Willis. Because of their anatomic variations, a large number of animals is needed. On account of the specific vulnerability of the hippocampus, striatum and neocortex, it is possible to evaluate the severity of the ischemic damage through an analysis of locomotor activity. The tests support the sensitvity of the experimental sample and compensate the interanimal variability., Methods: The locomotor pattern of 30 male Mongolian gerbils was recorded before they were subjected to experimental bilateral carotid clippage for 15 minutes followed by reperfusion. A transparent 75x50x90 cm acrylic box was filmed in order to determine the total distance covered by the animals in five minutes, for three consecutive days. The locomotor activity of the animals was also examined in an open field at 24 hours and seven days after ischemia. Serum neurospecific enolase (NSE) was measured in the ischemic group and compared with that of an intact control group., Results: The recording for normal animals was uniformly similar (average 200 squares in periphery), in the first trial of 3 consecutive days (188+/-6.7 S.D.). After ischemia, the numbers increased to 388 (+/- 40 S.D.), indicating that they were sensitive to the ischemic episode. Seven days later they returned to basal values. Serum NSE was high in the ischemic group versus the intact control group (S=<0.001)., Conclusions: Locomotor activity in an open field is a useful reference as a predictive test to determine the sensitivity of experimental animals to ischemia. It is also associated to the degree of cerebral damage in global ischemia-reperfusion, and this behavior is representative of the expression of selective ischemic injury. The determination of NSE is useful as an associated parameter of ischemic injury.

The effects of the intracerebroventricular (ICV) administration of crude extracts of lupin quinolizidine alkaloids (LQAs) were studied in adult rat brain tissue. Mature L. exaltatus and L. montanus seeds were collected in western Mexico, and the LQAs from these seeds were extracted and analyzed by capillary gas chromatography. This LQA extract was administered to the right lateral ventricle of adult rats through a stainless steel cannula on five consecutive days. While control animals received 10 microl of sesame oil daily (vehicle), the experimental rats (10 per group) received 20 ng of LQA from either L. exaltatus or from L. montanus. All the animals were sacrificed 40 h after receiving the last dose of alkaloids, and their brains were removed, fixed and coronal paraffin sections were stained with haematoxylin and eosin. Immediately after the administration of LQA the animals began grooming and suffered tachycardia, tachypnea, piloerection, tail erection, muscular contractions, loss of equilibrium, excitation, and unsteady walk. In the brains of the animals treated with LQA damaged neurons were identified. The most frequent abnormalities observed in this brain tissue were "red neurons" with shrunken eosinophilic cytoplasm, strongly stained pyknotic nuclei, neuronal swelling, spongiform neuropil, "ghost cells" (hypochromasia), and abundant neuronophagic figures in numerous brain areas. While some alterations in neurons were observed in control tissues, unlike those found in the animals treated with LQA these were not significant. Thus, the histopathological changes observed can be principally attributed to the administration of sparteine and lupanine present in the alkaloid extracts.

Aims: This work analyses the main studies dealing with the mechanisms by which the brain is altered by chronic stress and the impact of social stimuli on the activation of these mechanisms, which can lead to behavioural disorders and cognitive impairment in communities of mammals., Development: The physiological and hormonal responses triggered as a response to stress are linked to alterations in certain areas of the brain and more particularly in the hippocampus. These mechanisms include hyperactivity of the hypothalamus-pituitary-adrenal axis, raised levels of corticosteroids and excitatory amino acids, neurotoxicity due to intracellular accumulation of calcium, apoptosis and a number of factors having to do with the immunological system. Most of these studies have involved the exogenous application of supraphysiological levels of corticosteroids or challenging the individual with stimuli that do not properly belong to their natural surroundings. Nevertheless, it is also possible that these mechanisms are triggered by aversive social stimuli from the natural environment, such as confrontation, establishing hierarchies, neglect and social evaluation. It has been proved that social stress has important effects on conduct and health, especially with regard to the structural and functional integrity of the brain., Conclusions: Social stress can trigger important alterations in the nervous system of individuals exposed to it and these changes can manifest themselves as varying types of disorders affecting conduct and the cognitive skills. Nevertheless, not all natural surroundings give rise to these adverse effects, as balanced communities offer their members support, protection and a series of other advantages.

Background: High glucocorticoid serum levels and prednisone (PDN) therapy have been associated with depression, posttraumatic stress disorder, and some types of cognitive dysfunction in humans., Objective: The aim of this study was to assess whether chronic (90 days) PDN administration produces disturbance in learning and memory retention associated with neuronal degeneration and cerebral glial changes., Methods: Male Wistar rats were studied. Controls received 0.1 ml distilled water vehicle orally. The PDN group was treated orally with 5 mg/kg/d PDN, which is equivalent to moderate doses used in clinical settings. Learning and memory retention were assessed with the Morris water maze. The index of degenerated neurons as well as the number and cytoplasmic transformation of astrocytes and microglia cells were evaluated in the prefrontal cortex and the CA1 hippocampus., Results: PDN-treated rats showed a significant delay of 20% in learning and memory retention as compared with controls. In addition, in the PDN group, the neuronal degeneration index was two times higher in the prefrontal cortex, and approximately 10 times higher in the CA1 hippocampus, than in control animals. The number and cytoplasmic transformation of astrocytes were also significantly higher in the PDN group than in control animals. In the PDN-treated group, isolectin-B4-labeled microglia cells were higher in the prefrontal cortex but not in the hippocampus., Conclusion: These results suggest that chronic exposure to PDN produces learning and memory impairment, reduces neural viability, and increases glial reactivity in cerebral regions with these cognitive functions.

Recent studies confirm that astrocytes and neurons are associated with the synaptic transmission, particularly with the regulation of glutamate (Glu) levels. Therefore, they have the capacity to modulate the Glu released from neurons into the extracellular space. It has also been demonstrated an intense astrocytic and microglia response to physical or chemical lesions of the central nervous system. However, the persistence of the response of the glial cells in adult brain had not been previously reported, after the excitotoxic damage caused by neonatal dosage of monosodium glutamate (MSG) to newborn rats. In this study, 4 mg/g body weight of MSG were administered to newborn rats at 1, 3, 5, and 7 days after birth, at the age of 60 days the astrocytes and the microglia cells were analyzed with immunohistochemical methods in the fronto-parietal cortex. Double labeling to glial fibrillary acidic protein (GFAP) and BrdU, or isolectin-B(4) and BrdU identified astrocytes or microglia cells that proliferated; immunoblotting and immunoreactivity to vimentin served for assess immaturity of astrocytic intermediate filaments. The results show that the neonatal administration of MSG-induced reactivity of astrocytes and microglia cells in the fronto-parietal cortex, which was characterized by hyperplasia; an increased number of astrocytes and microglia cells that proliferated, hypertrophy; increased complexity of the cytoplasm extension of both glial cells and expression of RNAm to vimentin, with the presence of vimentin-positive astrocytes. This glial response to neuroexcitotoxic stimulus of Glu on the immature brain, which persisted to adulthood, suggests that the neurotransmitter Glu could trigger neuro-degenerative illnesses., (Copyright 2002 Wiley-Liss, Inc.)

A single dose of 5, 10 and 100 mg/kg of Casimiroa edulis aqueous extract (AQ); 10, 100 and 1000 mg/kg of C. edulis ethanolic extract (E-OH); in addition, 10, 30 and 12 mg/kg of propyleneglycol (Pg), phenytoin (Phen) and phenobarbital (Phb) was orally given to adult male Wistar rat groups. Thereafter, all groups were assayed for protection against maximal electroshock (MES) and pentylenetetrazole (METsc) seizure inducing tests at hourly intervals throughout 8 h. For MES, a maximal protection of 70% at the 2nd and 4th h with 10 mg/kg AQ and 100 mg/kg E-OH doses, occurred. That of Phen, Phb and Pg was 80, 90 and 10% at the 8th, 6th and 2nd h, respectively. The averaged values of the MES unprotected rats under 10 and 100 mg/kg of AQ and E-OH extracts, showed that a shortened reflex duration as well as a delayed latency and uprising times occurred. On the other hand, just an enlarged latency and no protection against METsc device in AQ and EOH was observed. Phen and Phb maximal protection was 80 and 100% at the 4th and 6th hour against METsc. Thus, AQ is tenfold more potent anticonvulsive extract than E-OH against MES.

Astrocytes are a target for steroid hormones and for steroids produced by the nervous system (neurosteroids). The effect of gonadal hormones and several neurosteroids in the formation of gliotic tissue has been assessed in adult male rats after a penetrating wound of the cerebral cortex and the hippocampal formation. The hormones testosterone, 17beta-estradiol and progesterone and the neurosteroids dehydroepiandrosterone, pregnenolone and pregnenolone sulfate resulted in a significant decrease in the accumulation of astrocytes in the proximity of the wound and in a decreased bromodeoxyuridine incorporation in reactive astrocytes. Of all steroids tested, dehydroepiandrosterone was the most potent inhibitor of gliotic tissue formation. These findings suggest that neurosteroids and sex steroids may affect brain repair by down-regulating gliotic tissue.

This is the first attempt to harden all organs of a body together without excising them. This process was accomplished in bottom-belted, gastrointestinal (GI) or intravenously (i.v.) catheterized dog cadavers so as to influx an electrolytic solution containing formaldehyde (ESF). The i.v. influx of ESF was found to be the best perfusion pathway. After 48 h of immersion in ESF, 24 h current time of 17.5 A of current intensity, 24 degrees to 56 degrees C, we ended up with thoroughly fixed dog cadavers that were wrapped with ethyl alcohol:glycerol gauzes and stored in plastic bags at room temperature. Optical microscopy of every sliced tissue showed normal blood vessels, neurons, glial and Purkinje cells and their nuclei of brain and cerebellum, respectively. Cardiac muscle fibers were of normal appearance. Kidney Bowman's capsule and space were found to be normal except for vacuolarly degenerated tubules. Small intestine showed normal epithelial cells and crypts of Lieberkühn. In liver, sinusoids were normally arrayed but showed vacuolar cell degeneration. Herein a method to attain an electrochemical whole body fixation is described.

An aqueous extract of Casimiroa edulis leaves was tested in adult male Wistar rats for anticonvulsant activity utilizing two models of experimental epilepsy: maximal electroshock seizure (MES) and subcutaneously injected metrazole (METsc). Single dose of 100 mg/kg C. edulis vacuum dried aqueous extracts (VDA) orally administered to experimental animals elicited 50% and 70% abolition of MES and METsc-induced seizures, respectively. Two firmly established antiepileptic drugs in human therapy, phenytoin (PHT) and phenobarbital (PB), abolished 90% of MES-induced seizures, whereas an 80% and 100% absence of clonic seizures was attained in METsc test, correspondingly. The seizure abolition observed in C. edulis VDA treated rats was comparable with the anticonvulsive pattern exhibited by PHT and PB. These results suggest that potencially antiepileptic compounds are present in C. edulis extracts that deserve the study of their identity and mechanism of action.

Cerebellar morphogenesis as well as somatometric parameters of progenies from mothers exposed to ethyl-ether, chloroform, turpentine or thinner were registered a 24, 48 and 7 hours of age. 1. Mortality rate of 20 and 59% was observed in progenies of thinner or turpentine exposed mothers, correspondingly. 2. Delay of intrauterine growth manifested by body weight, size and cephalic diameter was evident in chloroform exposed groups (P < 0.01). 3. Cerebellar maturation delay was found in thinner or turpentine prenatally exposed litters. 4. The number of Purkinje cells was significantly reduced in ethyl-ether and chloroform exposed groups (P < 0.01). These cells were found less affected by thinner or turpentine exposure (P < 0.01).

Phenytoin and its vehicle were orally administered to adult Sprague-Dawley rats during 7, 14 and 30 days at doses of 300 and 450 mg/kg/24 hr., respectively. We found: 1) Increased liver DNA concentration in subgroups of animals treated with 450 mg at 7 (P < 0.02) and 15 days (P < 0.001) Phenytoin serum levels were 19 ug/ml. 2) Increased protein concentration with 300 mg at 7 (P < 0.01) and 15 days (P < 0.001), respectively. 3) Cloudy swelling, vacuolar degeneration, liver sinusoids disappearance and lymphocytic cells infiltrate in subgroups of rats receiving vehicle throughout 6, 14 and 15 days correspondingly. The former lesion was found in all subgroups, except that 450 mg treated animals liver more severely affected. 4) Increased DNA concentration in kidney of subgroups receiving 450 mg/kg throughout 7 (P < 0.05), 15 (P < 0.001) and 30 days (P < 0.001), correspondingly. 5) Increased protein concentration in rats receiving 450 mg during 15 days (P < 0.001) and severely decreased at 30 days period. 6) Cloudy swelling was found in all treated animals subgroups. Seven cellular and tissue lesions were caused by vehicle at 15 and 30 days periods. 450 mg of phenytoin predominantly caused tissue condensation and vacuolar degeneration in kidney cortex. 7) propylene glycol do affect liver and kidney at doses below TD-50. Phenytoin stimulate kidney and liver cell proliferation. Caution should be observed when using parenteral phenytoin.

A modified antiepileptic screening procedure to test anticonvulsant drugs is shown. Diphenylhydantoin sodium salt (DFH-Na) and phenobarbital (Phb) were tested throughout 8 h, at hourly intervals after a single oral drug intake in rats. Another group was tested at steady stage of DFH-Na during 7 days period. A single dose of DFH-Na was orally administrated to male and female rats (30 mg/kg) and after testing throughout 8 h: 0, 5, 28, 38, 52, 70 and 75% and 10, 18, 50, 35, 62, 50 and 70% protection against MES, was found. Only 20% protection was found in females to METsc test on the 6th and 7th h. However, 80, 60, 60 and 20% males were found protected against METsc test from the 4th to the 8th hour. Maximum blood serum levels were 2 micrograms/ml. Phenobarbital at doses 12 mg/kg in males and females as well showed: 30, 64, 66, 74, 84, 90, 40, 34% and 14, 36, 53, 41, 55, 70, 82 and 82% protection against MES, respectively. On the other hand, 60, 60, 46, 47, 94, 100, 80 and 20% and 80, 80, 46, 70, 60, 40, 80 and 20% of males and females were protected against METsc test, respectively. An average of 8 micrograms/ml and 12 micrograms/ml of Phb serum levels were found since the 1 to the 8th and 5th hours, correspondingly. A 28% protection of both male and female rats to MES test was found following 7 days of treatment with DFH-Na (30 mg/kg) treatment. Also an average of 10% female and males were found protected against METsc test.

Sodium diphenylhydantoin (DFH-Na) is the drug of choice to control convulsive seizure disorders. Beneficial as well as adverse effects of DFH-Na have been reported to occur since 1938. Thus, the present article deals with the effect that 2.5, 5, 10, 15, 20 and 100 mg/kg/day (2.5, 5, 10, 15, 20 and 100) might cause on Cerebrum (C), Cerebellum (Cb) and liver (L) DNA [DNA] and Protein [Pr] concentration. Our results showed that: 1) DNA-C-14 (15, 20 and 100) were found decreased when compared to control (p less than 0.001) and [DNA]-C-30 (15, 20 and 100) as well (p less than 0.001). [Pr]-C-7, 14, 30 (2.5, 5, 10, 15, 20 and 100) showed no statistically important differences. 2) [DNA]-Cb-14 (15 and 20) were found lower than control (p less than 0.05) and [DNA]-Cb-30 (15 and 20) as well (p less than 0.05). [Pr]-Cb-14,30 (100) was found decreased (p less than 0.05). 3) [DNA]-L-14 (10, 15, 20 and 100) was found decreased when compared to control (p less than 0.001) and [DNA]-L-30 (10, 15, 20 and 100) as well (p less than 0.001). [Pr]-L-7, 14 and 30 (2.5, 5, 10, 15, 20 and 100) were found lower than control (p less than 0.05). A bimodal pattern of [DNA] of C. Cb and L was demonstrated to occur with i.p. injected DFH-Na.

Human skin biotransform naturally occurring steroid hormones. 4-14C progesterone skin fate might involve C-19 derivates formation. In vitro incubation of 4-14C-progesterone with defammation. human abdominal skin minces for 5 days periods, predominantly yield: 1) Metabolites reduced at C-20 and C-5 positions of 4-14C progesterone. 2) 4-pregnen-17 01-20-one (0.85%). 3) 4-Androsten-17-01-3-one isolated as an acetylated derivative (0.29%). 4) A metabolite that behaves like 4-androsten-3, 17-diol. The metabolites identity was established through repeated cocrystallizations with known purified carriers in different organic solvents 17 -hydroxy-progesterone was found at greater concentrations in the group of polar metabolites. These metabolites are of biochemical interest but can not be assessed until the effects of these compounds on human skin are known.

1. Chronic morphine administration to rats produced diverse ultrastructural alterations in nerve cells and neuropile of caudate nucleus, cerebral cortex and hippocampus through a short term abstinence period. 2. All areas studied showed increasing damage related to time elapsed between the last morphine injection and animal sacrifice. 3. Intracytoplasmic neuronal membranous organelles mainly suffered severe swelling, membrane disarrangement and eventually cell disruption in all areas studied. 4. Hippocampus was the most affected area throughout the study, followed by caudate nucleus and cerebral cortex, where focal damage was seen. 5. Susceptibility to morphine cytotoxic effect in the three areas studied appears to be unrelated to their opiate receptor density. 6. Mitochondrial alterations produced by morphine could be related to interference of the intracellular energy production system and consequent unrestricted cell membrane permeability to water and solutes.

Progesterone -6,7-3H (P*) was incubated in minces of human secretory and proliferative endometrium in absence as well as in presence of 10 and 100 micrograms/ml of unlabelled progesterone (P), in Eagle's Culture Medium throughout 72h. The following metabolites of P* were found in culture media: 1. C-21 derivatives of P* reduced at C-5, and C-20 positions. Also, a 3 beta-hydroxy-5 alpha pregnane-20-One conjugated to a glucuronic acid moiety was identified. 2. Concentrations of water-soluble derivative accounted for 21% and 29% of the recovered radioactivity in proliferative and secretory endometria, respectively. 3. After beta-glucuronidase cleavage, 80% to 95% of the water soluble derivatives were released as free steroids. 4. Approximately 60% corresponded to 3 beta -hydroxy- 5 alpha pregnane-20-one of the pooled water extracts. 5. Alson, 17% and 13% as well as 9% and 8% recoveries under 10 and 100 micrograms/P were observed in proliferative and secretory endometria, respectively. Glucuronidation seems to be a compensatory route to metabolize P and P* in human endometrium as might also occur in other species.

Excised cornea from adult New Zealand rabbits were incubated with progesterone-4-14C in Eagle's media for 96 hr. Samples were inactivated at intervals of 24 hr incubation periods. The following metabolites of progesterone were isolated: 20 alpha-Hydroxy-4-pregnen-3-one, 20-hydroxy-4-pregnen-3-one, 5 alpha-pregnane-3,20-dione; 5 beta-pregnane-3,20-dione and 6 beta-hydroxy-4-pregnen-3,20-dione. 20 alpha-Hydroxy-pregnen-3-one was the predominant metabolite of progesterone-4-14C. A linear increase was observed throughout 96 hr. The opposite was found for 5 alpha and 5 beta pregnane-3,20-dione. Compounds remaining at the origin of the paper chromatograms contained 6 beta-hydroxy-4-pregnen-3,20-dione and other still unidentified metabolites of progesterone-4-14C. Presence of 20 alpha and 20 beta-reductase; 5 alpha and 5 beta-reductase and 6 beta-hydroxylase enzyme systems are involved in corneal progesterone metabolism. No fungal neither bacterial enzymatic biotransformation occurred in the culture media.