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Biomedical subjects

M Otsuka

Publications and source records attributed to M Otsuka.

At least 487 records · Page 27Linked to original sources
PubMed1979

Enkephalins presynaptically inhibit cholinergic transmission in sympathetic ganglia.

Recent biochemical and immunohistochemical studies have shown that the opioid peptides, enkephalins, occur in nerve terminals and cell bodies in mammalian sympathetic ganglia1-3. Opiates and enkephalins are thought to inhibit synaptic transmission in the peripheral nervous tissues as well as in the central nervous system4-12. The mechanisms of the opiate actions, however, are not entirely clear; both pre- and postsynaptic sites of action have been proposed7-9,11,12. As acetylcholine is known to be the major neurotransmitter in the autonomic ganglia and as the mechanism of synaptic transmission is well clarified13, analysis of the peptide action could be more easily but equally usefully carried out in the peripheral synapses than in central synapses. We now report that enkephalins presynaptically inhibit cholinergic transmission in sympathetic ganglia.

Acetylcholine↗
PubMed1979

Substance P: depletion in the dorsal horn of rat spinal cord after section of the peripheral processes of primary sensory neurons.

The substance P content, glutamic acid decarboxylase and choline acetyltransferase activities and the level of [3H]diprenorphine binding were measured in various regions of the lumbar spinal cord of rats after unilateral section of the sciatic nerve or after dorsal rhizotomy. Sciatic nerve section produced a 75--80% depletion of substance P in the dorsal horn but did not change the substance P content of the ventral horn. The onset of substance P depletion occurred within 7 days and was maintained for 2 months. The substance P content of the dorsal root ganglia and both the peripheral and central branches of primary sensory neurons was also reduced after sciatic nerve section. Glutamic acid decarboxylase and choline acetyltransferase activity were unchanged; however, a small decrease in opiate receptor binding occurred 1 month after nerve section. Dorsal rhizotomy produced an 80% depletion of substance P in the dorsal horn. In addition, the substance P content of the ventral horn was significantly reduced. Glutamic acid decarboxylase activity in the dorsal horn was unaffected by dorsal rhizotomy whereas opiate receptor binding was reduced by 40%. From these studies it appears that peripheral nerve injury results in the degeneration of primary sensory neurons which contain and release substance P as neurotransmitter.

Afferent Pathways↗
PubMed1979

Induction of pre-early nuclear antigen(s) in HEL cells infected with human cytomegalovirus.

Human cytomegalovirus (HCMV)-specific nuclear antigen could be detected within 1 hr after infection in human embryo lung cells by the anticomplement immunofluorescence (ACIF) test. This antigen has been named the pre-early nuclear antigen (PENA) in this paper. Serum absorption tests suggested that PENA is immunologically different from the early antigen and the major nuclear inclusion antigens detected by the indirect immunofluorescence test before and after viral DNA replication, respectively. PENA-forming ability of the virus corresponded to its plaque forming ability. PENA formation was not affected by phosphonoacetate but was inhibited by the addition of inhibitors of RNA and protein syntheses or by UV-irradiation of infecting virus, suggesting that the formation of PENA depends on the expression of infecting virus gene functions. Virus-specific proteins were isolated by indirect immunoprecipitation from HCMV-infected cells exposed to 35S-methionine. SDS-polyacrylamide gel electrophoresis of the immunoprecipitate showed that at least two species of virus-specific polypeptides with molecular weights o.f 70,000 and 30,000 were synthesized de novo within 3 hr after infection.

Antigens↗
PubMed1979

Pharmacological study of [2-chloro-11-(2-dimethylaminoethoxy) dibenzo[b,f]thiepine] (zotepine), a new neuroleptic drug.

2-Chloro-11-(2-dimethyl-aminoethoxy)dibenzo [b,f]thiepine (zotepine) is a new neuroleptic drug with a chemical structure different from known neuroleptics. The psychopharmacological effects of zotepine in mice, rats and dogs were studied and compared with those of commercially available neuroleptics. Haloperidol and perphenazine were the most active and thioridazine was the least active in hibiting apomorphine-induced gnawing and circling movement, methamphetamine-induced gnawing and circling movement, conditioned avoidance response, motor activity, dopamine-induced pancreatic secretion and apomorphine-induced vomiting. These drugs also had the same order of potency in inducing catalepsy and increasing dopamine turnover and prolactin release. Chlorpromazine, propericiazine and thiothixene were intermediate in potency. Zotepine equalled chlorpromazine in most activities, however, it was clearly less active than chlorpromazine in potentiation of barbiturate sleep and cardiovascular effect.

Animals↗
PubMed1976

Substance P and primary afferent transmission.

Substance P has a powerful excitant action on spinal motoneurons of the newborn rat, and the action is specifically antagonized by Lioresal, which also readily blocks spinal reflexes involving primary afferent transmission. Substance P is highly concentrated in bovine and feline dorsal roots as well as in the dorsal part of the dorsal horn of cat spinal cord. There is evidence that substance P is synthesized in spinal ganglia, transported through the dorsal roots and stored in the axon terminals of primary afferent neurons. These and other results suggest that the undecapeptide substance P, or one of its shorter C-terminal analogues, functions as an excitatory transmitter of the primary afferent fibers.

Amino Acid Sequence↗
PubMed1975

Regional distribution of substance P in the spinal cord and nerve roots of the cat and the effect of dorsal root section.

Chemical properties of substance P in the spinal cord and dorsal roots of the cat were examined by gel chromatography and paper electrophoresis. The results suggest that the substance is identical with the undecapeptide, hypothalamic substance P, recently isolated from bovine hypothalamus. Distribution of substance P in the cat spinal cord (L5-S1) was investigated. Substance P was highly concentrated in the dorsal horn, where the highest level was found in the dorsal part. After the unilateral ligation and/or section of the dorsal roots, the level of substance P in the dorsal horn, particularly in its dorsal part, was markedly lowered. In the ligated and sectioned dorsal root, substance P was highly accumulated on the ganglion side, whereas its level was lowered on the central side of the ligature. These results suggest that hypothalamic substance P synthesized in the spinal ganglia is transported in the dorsal root toward their intraspinal axon terminals, where the substance is concentrated and serves as a neurotransmitter.

Animals↗