Sex-specific 24-h acetylcholine release profile in the medial prefrontal cortex: simultaneous measurement of spontaneous locomotor activity in behaving rats.

The difference in visual object recognition by males and females suggests a sex-specific function in the medial prefrontal cortex (mPFC). In the present study, we performed an in vivo microdialysis study in three groups of rats (males, diestrous females, and proestrous females) to examine the potential sex difference in acetylcholine (ACh) release in the mPFC. The dialysate was automatically collected from the mPFC every 20 min for 24 h under freely moving conditions and the spontaneous locomotor activity was simultaneously monitored. Although ACh release in the mPFC during the dark phase was significantly greater than during the light phase in both sexes, the female rats consistently exhibited a significantly greater mean ACh release than the males. Spontaneous locomotor activity during the dark phase was also significantly greater than during the light phase in both sexes, but the females exhibited significantly greater spontaneous locomotor activity than the males. In addition, both sexes of rats were found to have significant positive correlations between ACh release and spontaneous locomotor activity, but females were found to have significantly greater correlation coefficients than males. Stereological methods were used to examine the number of choline acetyltransferase immunoreactive cells in the nucleus basalis magnocellularis and the horizontal diagonal band of Broca. The number of choline acetyltransferase immunoreactive cells in the nucleus basalis magnocellularis was also greater in females than males, suggesting a contribution to the higher ACh release in females. In contrast, no sex difference in the choline acetyltransferase immunoreactive cells was observed in the horizontal diagonal band of Broca. This is the first report to show a sex difference in the 24-h ACh release profile in the mPFC of behaving rats.

DOPA cyclohexyl ester, a DOPA antagonist, blocks the depressor responses elicited by microinjections of nicotine into the nucleus tractus solitarii of rats.

Nicotinic cholinergic receptors play a role in cardiovascular regulation in the lower brain stem. Herein, we present evidence that l-3,4-dihydroxyphenylalanine (DOPA), a putative neurotransmitter in the central nervous system, is involved in the depressor response to microinjection of nicotine into the nucleus tractus solitarii (NTS). Microinjection of nicotine into the medial area of the NTS led to decreases in arterial blood pressure and heart rate in anesthetized rats. Mecamylamine, a nicotinic receptor antagonist, microinjected into NTS, blocked the depressor and bradycardic responses to nicotine. Nicotine-induced depressor and bradycardic responses were blocked by DOPA cyclohexyl ester (DOPA CHE), an antagonist for DOPA. DOPA CHE did not modify the action of carbachol on excitatory postsynaptic potential in rat cortical slices. These results suggest that endogenous DOPA is involved in nicotine-induced depressor responses in the NTS of anesthetized rats.

L-3,4-dihydroxyphenylalanine-induced c-Fos expression in the CNS under inhibition of central aromatic L-amino acid decarboxylase.

L-3,4-dihydroxyphenylalanine (DOPA) is a neurotransmitter candidate. To map the DOPAergic system functionally, DOPA-induced c-Fos expression was detected under inhibition of central aromatic L-amino acid decarboxylase (AADC). In rats treated with a central AADC inhibitor, DOPA significantly increased the number of c-Fos-positive nuclei in the paraventricular nuclei (PVN) and the nucleus tractus solitarii (NTS), and showed a tendency to increase in the supraoptic nuclei (SON), but not in the striatum. On the other hand, DOPA with a peripheral AADC inhibitor elevated the level of c-Fos-positive nuclei in the four regions, suggesting that DOPA itself induces c-Fos expression in the SON, PVN and NTS. In rats treated with 6-hydroxydopamine (6-OHDA) to lesion the nigrostriatal dopamine (DA) pathway, DOPA significantly induced c-Fos expression in the four regions under the inhibition of peripheral AADC. However, under the inhibition of central AADC, DOPA did not significantly increase the number of c-Fos-positive nuclei in the four regions, suggesting that DOPA at least in part induces c-Fos expression through its conversion to DA. It was likely that the 6-OHDA lesion enhanced the response to DA, but attenuated that to DOPA itself. In conclusion, we proposed that the SON, PVN and NTS include target sites for DOPA itself.

The involvement of the stimulatory G protein in sexual dimorphism of beta-adrenergic receptor-mediated functions in rat liver.

In rat hepatocytes, beta-adrenergic receptor (beta-AR)-mediated cAMP generation was found to be higher in the female than in the male. As compared to the male, the number of beta-AR, detected by [125I]iodocyanopindolol, was elevated in the female. In agonist competition experiments, the proportion of beta-AR in the high-affinity state was promoted in the female than in the male. The alpha subunit of the stimulatory G protein (Gs alpha) was quantified using ADP-ribosylation catalyzed by cholera toxin. The amount of Gs alpha, both small, 42 kDa (Gs alpha S), and large, 47 kDa (Gs alpha L), forms increased in parallel with enhancement of catecholamine-sensitive adenylate cyclase activity in the female. The female showed a disproportionate increase in Gs alpha L, which is preferentially coupled to beta-AR, compared with Gs alpha S. In addition, 17 beta-estradiol facilitated isoproterenol-induced cAMP generation in both male and female rats, whereas castration or testosterone had no effect on this response. It is proposed that the cellular sites for sexual dimorphism in hepatic beta-adrenergic functions are the coupling state of beta-AR to Gs and the amount of Gs alpha as well as the level of beta-AR.

Alterations in the stimulatory G protein of the rat liver after partial hepatectomy.

In adult male rat livers, cAMP generation in response to beta-adrenergic agonists was dramatically stimulated after partial hepatectomy. Quantitation of the alpha subunits of the stimulatory G protein (Gs alpha) using ADP-ribosylation catalyzed by cholera toxin revealed the increment in the amounts of two forms of Gs alpha, Gs alpha-S and Gs alpha-L, during liver regeneration. These increases in the amounts of both Gs alpha proteins were associated with the stimulation in their mRNA levels. In addition, partial hepatectomy gave rise to a shift in the proportion of beta-adrenergic receptor (beta-AR) in the high affinity state produced by beta-AR-Gs complex. The susceptibility of Gs alpha to trypsin was used as a probe for beta-AR-Gs coupling. The GTP-bound forms of both Gs alpha-S and Gs alpha-L were more trypsin-sensitive than their GDP-bound forms. Preincubation of liver plasma membranes prepared from partially hepatectomized rats with the agonist isoproterenol resulted in an enhancement of trypsin-sensitivity of Gs alpha-L, but not Gs alpha-S. This effect was retarded by the addition of the antagonist propranolol. We conclude that the increase in the amount of Gs alpha can be contributed to the rise in beta-response after partial hepatectomy, and suggest that beta-AR is preferentially coupled with Gs alpha-L rather than Gs alpha-S.

S-2474, a novel nonsteroidal anti-inflammatory drug, rescues cortical neurons from human group IIA secretory phospholipase A(2)-induced apoptosis.

The elevated level of group IIA secretory phospholipase A(2) (sPLA(2)-IIA) activity contributes to neurodegeneration in the cerebral cortex after ischemia. The up-regulation of cyclooxygenase-2 (COX-2) is also relevant to cerebral ischemia in humans. Studies of ischemia with COX-2 inhibitors suggest a clinical benefit. In the present study, we investigated effects of S-2474 on sPLA(2)-IIA-induced cell death in primary cultures of rat cortical neurons, which was established as an in vitro model of brain ischemia. S-2474 is a novel nonsteroidal anti-inflammatory drug (NSAID), which inhibits COX-2 and contains the di-tert-butylphenol antioxidant moiety. S-2474 significantly prevented neurons from undergoing sPLA(2)-IIA-induced cell death. S-2474 completely ameliorated sPLA(2)-IIA-induced apoptotic features such as the condensation of chromatin and the fragmentation of DNA. sPLA(2) also generated neurotoxic prostaglandin D(2) (PGD(2)) and free radicals from neurons before cell death. S-2474 significantly inhibited the sPLA(2)-IIA-induced generation of PGD(2). The present cortical cultures contained few non-neuronal cells, indicating that S-2474 affected neuronal survival directly, but not indirectly via non-neuronal cells. The inhibitory effect of S-2474 on COX-2 might contribute to its neuroprotective effect. In conclusion, S-2474 exhibits neuroprotective effects against sPLA(2)-IIA. Furthermore, the present study suggests that S-2474 may possess therapeutic potential for stroke via ameliorating neurodegeneration.

Adenosine di-, tri- and tetraphosphopyridoxals modify the same lysyl residue at the ATP-binding site in adenylate kinase.

Adenosine diphosphopyridoxal modifies Lys-21 in adenylate kinase which is located in a glycine-rich loop [(1987) J. Biol. Chem. 262, 8257-8261]. We presently report that adenosine tri- and tetraphosphopyridoxals modify the same lysyl residue more rapidly than the diphospho compound does. However, susceptibilities of the Schiff bases between the labels and the lysyl residue to sodium borohydride considerably differ in the modifications with the three reagents. These observations seem to be ascribable to the mobility of the epsilon-amino group of Lys-21 in the active-site region of the enzyme.

Mastoparan, a peptide toxin from wasp venom, stimulates glycogenolysis mediated by an increase of the cytosolic free Ca2+ concentration but not by an increase of cAMP in rat hepatocytes.

A wasp venom, mastoparan, rapidly increased the cytosolic free Ca2+ concentration [( Ca2+]i) and activated phosphorylase in rat hepatocytes in a concentration-dependent manner. Mastoparan could increase [Ca2+]i even in the absence of extracellular Ca2+, but a larger increase was observed in the presence of extracellular Ca2+. Thus, mastoparan mobilized Ca2+ from intracellular and extracellular Ca2+ stores. It also activated inositol triphosphate (IP3) accumulation, but did not stimulate cAMP production. From these results, we conclude that mastoparan activates rat hepatic glycogenolysis mediated by the accumulation of IP3, which causes an increase of [Ca2+]i but not that mediated by cAMP.

Gas6 rescues cortical neurons from amyloid beta protein-induced apoptosis.

Gas6, a product of the growth-arrest-specific gene 6, protects neurons from serum deprivation-induced apoptosis. Neuronal apoptosis is also caused by amyloid beta protein (Abeta), whose accumulation in the brain is a characteristic feature of Alzheimer's disease. Abeta induces Ca(2+) influx via L-type voltage-dependent calcium channels (L-VSCCs), leading to its neurotoxicity. In the present study, we investigated effects of Gas6 on Abeta-induced cell death in primary cultures of rat cortical neurons. Abeta caused neuronal cell death in a concentration- and time-dependent manner. Gas6 significantly prevented neurons from Abeta-induced cell death. Gas6 ameliorated Abeta-induced apoptotic features such as the condensation of chromatin and the fragmentation of DNA. Prior to cell death, Abeta increased influx of Ca(2+) into neurons through L-VSCCs. Gas6 significantly inhibited the Abeta-induced Ca(2+) influx. The inhibitor of L-VSCCs also suppressed Abeta-induced neuronal cell death. The present cortical cultures contained few non-neuronal cells, indicating that Gas6 affected the survival of neurons directly, but not indirectly via non-neuronal cells. In conclusion, we demonstrate that Gas6 rescues cortical neurons from Abeta-induced apoptosis. Furthermore, the present study indicates that inhibition of L-VSCC contributes to the neuroprotective effect of Gas6.

Effects of S-2474, a novel nonsteroidal anti-inflammatory drug, on amyloid beta protein-induced neuronal cell death.

1. The accumulation of amyloid beta protein (Abeta) in the brain is a characteristic feature of Alzheimer's disease (AD). Clinical trials of AD patients with nonsteroidal anti-inflammatory drugs (NSAIDs) indicate a clinical benefit. NSAIDs are presumed to act by suppressing inhibiting chronic inflammation in the brain of AD patients. 2. In the present study, we investigated effects of S-2474 on Abeta-induced cell death in primary cultures of rat cortical neurons. 3. S-2474 is a novel NSAID, which inhibits cyclo-oxygenase-2 (COX-2) and contains the di-tert-butylphenol antioxidant moiety. S-2474 significantly prevented neurons from Abeta(25 - 35)- and Abeta(1 - 40)-induced cell death. S-2474 ameliorated Abeta-induced apoptotic features such as the condensation of chromatin and the fragmentation of DNA completely. 4. Prior to cell death, Abeta(25 - 35) generated prostaglandin D(2) (PGD(2)) and free radicals from neurons. PGD(2) is a product of cyclo-oxygenase (COX), and caused neuronal cell death. 5. S-2474 significantly inhibited the Abeta(25 - 35)-induced generation of PGD(2) and free radicals. 6. The present cortical cultures contained little non-neuronal cells, indicating that S-2474 affected neuronal survival directly, but not indirectly via non-neuronal cells. Both an inhibitory effect of COX-2 and an antioxidant effect might contribute to the neuroprotective effects of S-2474. 7. In conclusion, S-2474 exhibits protective effects against neurotoxicity of Abeta. Furthermore, the present study suggests that S-2474 may possess therapeutic potential for AD via ameliorating degeneration in neurons as well as suppressing chronic inflammation in non-neuronal cells.

Deterioration of axotomy-induced neurodegeneration by group IIA secretory phospholipase A2.

Phospholipase A2 (PLA2) is proposed to play a role in the repair of the ruptured membrane after axotomy. In neonatal rats, we examined the effect of Group IIA secretory PLA2 (sPLA2-IIA) on axotomy-induced cell death of motoneurons. sPLA2-IIA significantly induced death of axotomized motoneurons. Indoxam, a specific inhibitor for sPLA2-IIA, protected motoneurons from the sPLA2-IIA-induced deterioration. The present study indicated that sPLA2-IIA possessed neurotoxic effect rather than neuroprotective effect against facial nerve.

Chlorpromazine reduces toxicity and Ca2+ uptake induced by amyloid beta protein (25-35) in vitro.

Amyloid beta protein (A beta), has been reported to be toxic to neurons in vitro. However, the molecular mechanism leading to neuronal death remains unknown. Here we report protective effects of phenothiazines, a class of neuroleptic agent, against A beta toxicity in primary cultures of rat cortical neurons and PC12 cells. beta(25-35), an active sequence of A beta, showed dose-dependent reduction of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide dye (MTT) reductivity, and chlorpromazine (CPZ), promethazine or trifluoperazine restored it at micromolar concentration. The significant increase in Ca2+ uptake by chronic treatment of beta(25-35) was reduced not only by nimodipine but also by CPZ. These results suggest that phenothiazines attenuate beta(25-35) toxicity possibly by reducing of Ca2+ influx through L-type Ca2+ channels.

alpha-eudesmol, a P/Q-type Ca(2+) channel blocker, inhibits neurogenic vasodilation and extravasation following electrical stimulation of trigeminal ganglion.

In this study, we investigated the effect of alpha-eudesmol, which potently inhibits the presynaptic omega-agatoxin IVA-sensitive (P/Q-type) Ca(2+) channel, on neurogenic inflammation following electrical stimulation of rat trigeminal ganglion. Treatment with alpha-eudesmol (0.1-1 mg/kg. i.v.) dose-dependently attenuated neurogenic vasodilation in facial skin monitored by a laser Doppler flowmetry. In addition, alpha-eudesmol (1 mg/kg. i.v.) significantly decreased dural plasma extravasation in analysis using Evans blue as a plasma marker. On the other hand, alpha-eudesmol (1 mg/kg, i.v.) did not affect mean arterial blood pressure in rats. The calcitonin gene-related peptide (CGRP) and substance P (SP) released from activated sensory nerves have recently been suggested to be associated with the neurogenic inflammation. In this study, we also showed that alpha-eudesmol (0.45-45 microM) concentration-dependently inhibits the depolarization-evoked CGRP and SP release from sensory nerve terminals in spinal cord slices. These results indicate that the anti-neurogenic inflammation action of alpha-eudesmol, which does not affect the cardiovascular system, may be due to its presynaptic inhibition of the neuropeptide release from perivascular trigeminal terminals. We also suggest that the omega-agatoxin IVA-sensitive Ca(2+) channel blocker, alpha-eudesmol, may become useful for the treatment of the neurogenic inflammation in the trigemino-vascular system such as migraine.

Protein kinase inhibitor attenuates apoptotic cell death induced by amyloid beta protein in culture of the rat cerebral cortex.

Amyloid beta protein (A beta) is deposited characteristically in the brain of patients with Alzheimer's disease. Effects of protein kinase inhibitors (H-89, H-7, KN-62) on A beta-induced neuronal cell death were examined in primary culture of dissociated cerebral cortical cells. beta(25-35), the active fragment of A beta, induced neuronal cell death with apoptotic features including chromatin condensation and DNA fragmentation. The cell death was attenuated by cycloheximide or by H-89, a specific protein kinase A (PKA) inhibitor, but not by H-7 or KN-62. These data suggest that beta(25-35) induces apoptotic cell death through the PKA-mediated pathway.

Endotoxin contamination in wound dressings made of natural biomaterials.

Contamination by endotoxin of nine kinds of wound dressings made of natural biomaterials (calcium alginate, collagen, chitin, and poly-L-leucine) was examined with the use of water extracts. By applying the Limulus amoebocyte lysate (LAL) test, high concentrations of endotoxin were detected in extracts from three kinds of products made of calcium alginate. These extracts evoked fever in rabbits and induced the release of a proinflammatory (pyrogenic) cytokine, interleukin-6 (IL-6), from human monocytic cells (MM6-CA8). The effects disappeared when the extracts were treated with endotoxin-removing gel column chromatography or with an endotoxin antagonist, B464, confirming that the contaminating pyrogen was endotoxin. A noteworthy finding was that one of the endotoxin-containing extracts showed very weak IL-6-inducibility in human monocytic cells in contrast to its high pyrogenicity to rabbits. The discrepancy could be explained based on differences between humans and rabbits in sensitivity to the endotoxin, because the extract showed higher proinflammatory-cytokine (TNF-alpha)-inducibility in rabbit whole-blood cells (WBCs) than human WBCs. The results suggest that the LAL test is a useful method of detecting endotoxin contamination in wound dressings and the MM6-CA8 assay is a good supplement to the LAL test for evaluating pyrogenicity in humans accurately.

Transit time analysis of forced expiration in workers exposed to dust: a cross-sectional study.

Maximal expiratory flow at 25% forced vital capacity (V25), V25 divided by height (V25/HT), and mean transit time (MTT) were calculated from the same forced expiratory maneuver performed in welding workers. The values were compared to determine variations between individuals and changes with age and chest X-ray findings. The results showed that MTT may be a less variable and equally sensitive measurement of the function of peripheral airways as compared with V25 and V25/HT. Its usefulness in the detection of the early changes of pneumoconiosis, however, must be further investigated in a prospective cohort study on workers exposed to various kinds of dust.

Effect of lifetime cigarette consumption on time domain spirogram indices.

A cross-sectional analysis on the dose-related change in time domain spirogram indices induced by lifetime cigarette consumption was conducted to examine the ability of those indices to detect early changes in the lung periphery in comparison with conventional spirometric indices. The subjects were asymptomatic healthy male workers from three occupational cohorts including asbestos workers and welders. They were asked to perform the forced expiration maneuver at least three times to obtain reliable results. A total of 893 subjects were enrolled in the study, and 484 of them who were aged 30 years or more and were free from chronic respiratory symptoms and abnormalities in chest radiography and spirometry, were analyzed. Although conventional indices, such as forced expiratory volume in one second and maximal midexpiratory flow, were not significantly different between smokers and nonsmokers, the standard deviation of transit times and of time constant distribution in smokers were significantly elevated compared with nonsmokers. Furthermore a dose-related change according to lifetime cigarette consumption was observed in those indices. We conclude that time domain spirogram indices, especially the standard deviation of time constant distribution, would be more useful than conventional indices in detecting early changes in the lung periphery.

[Plant defense-related proteins as latex allergens].

Immediate-type allergic reactions to latex products made from natural rubber are called latex allergy. One of the notable features of latex-allergic people is their cross-reactivity to various vegetable foods and pollen. The structurally similar proteins which most kinds of plants potentially induce must be responsible for these cross-reactions. However, the taxonomical dissimilarity among the causative plants has kept us from concrete explanations of such cross-reactive allergens. We have speculated that plant defense-related proteins are a possible cause of the latex allergy. The well-known serologic relationships and sequence similarities of these ubiquitous plant proteins can explain the cross-reactivity without difficulty. Rubber trees cultured in plantation farms are repeatedly tapped and treated with phytohormones. These stresses would result in the significant induction of defense-related proteins. Indeed, we were able to detect defense-related enzymes in latex extracts. Moreover, three hydrolytic enzymes (beta-1,3-glucanase, chitinase/lysozyme, and carboxylesterase) that are very likely to take a defensive role were specifically recognized by the IgE antibodies of latex-allergic people and atopic patients. These experimental results strongly support our hypothesis. Because of their conserved structures, defense-related proteins should form a family of plant pan-allergens.

[Relationship between factors examined at health examination and serum pepsinogen levels in healthy adults. Physical measurements, blood chemical tests, drinking and smoking].

OBJECTIVE: We measured serum pepsinogen (PG) levels in healthy adults and examined their physical measurements, blood chemical test values, current drinking and smoking to investigate relationships between these factors and levels of serum PG components (serum PG I, PG II and PG I/II ratio). SUBJECTS AND METHODS: A total of 452 male adults in their 40's, who were determined to be normal or to have only chronic gastritis by endoscopy or X-ray examination of the upper gastrointestinal tract, were studied. PG I and PG II levels in sera were measured, and their relationship with physical measurements and blood chemical test values, and also with current amounts of drinking and smoking, were examined. RESULTS: 1) Height, body weight, body surface area, GOT, GPT and creatinine were found to significantly differ according to serum PG I level; body surface area, GPT and ALP significantly differed according to serum PG II level. However, none of the factors examined showed any significant correlation with the PG I/II ratio. 2) When subjects were divided into positive and negative cases using the evaluation criteria of PG components for gastric cancer screening (determined as positive on the basis of serum PG I level < or = 70 ng/ml and PG I/II ratio < or = 3.0), proposed by Miki et al., none of the factors differed significantly between the two groups. CONCLUSIONS: 1) Serum PG levels were associated with stature, serum transaminase and creatinine. 2) Although serum PG levels were associated with several factors, the effect of physical measurements and blood chemical tests on the results of the evaluation criteria of PG components proposed by Miki et al, were not remarkable.

L-type voltage-dependent calcium channels as therapeutic targets for neurodegenerative diseases.

Ca(2+) is a highly versatile intracellular second messenger in the central nervous system, and regulates many complicated cellular processes, including excitation, plasticity and apoptosis. Influx of Ca(2+) from the extracellular fluid is required for sustained elevation of the cytosolic Ca(2+) concentration and full activation of Ca(2+)-dependent processes. Voltage-dependent Ca(2+) channels (VDCCs) serve as the principal routes of Ca(2+) entry into electrically excitable cells such as neurons. The nervous system expresses VDCCs with unique cellular and subcellular distribution and specific functions. L-type voltage-dependent Ca(2+) channels (L-VDCCs) are distributed at neuronal cell bodies, dendrites and spines, and the postsynaptic L-VDCCs regulate neuronal excitability and gene expression. Presynaptic P/Qand N-type VDCCs trigger neurotransmitter release, and T-type channels support neuronal rhythmic burst firing. Evidence from natural mutants, knockout mice, and human genetic disorders indicates a fundamental role of some VDCCs in a wide variety of neurological disorders, including vascular dementia (VaD), Alzheimer's disease (AD), Parkinson's disease (PD) and Prion disease. Amyloid ß peptides, causative factors for AD, potentiate the influx of Ca(2+) into neurons via L-VDCCs. L-VDCCs blockers prevent neurons from undergoing amyloid ß-induced apoptosis. The present review highlights some recent findings on biochemical characterizations, physiological functions, pathological roles and pharmacological applications of the L-VDCCs and their implication in neurologic diseases.