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Biomedical subjects

J Yamada

Publications and source records attributed to J Yamada.

At least 379 records · Page 21Linked to original sources
PubMed1987

Pharmacological analysis of the variation in behavioural responses to tryptamine in five strains of mice.

The effects of tryptamine on behaviour were studied in five strains of mice. There were significant strain differences in the intensity of the 5-HT syndrome (head weaving and hindlimb abduction) and head twitch responses. The intensity of the 5-HT syndrome correlated significantly with the brain tryptamine content, although the occurrence of head twitch was unrelated. The 5-HT2 receptor antagonist, ketanserin, antagonized the head twitch responses elicited by tryptamine without affecting the head weaving or hindlimb abduction. Metergoline, an antagonist of both the 5-HT1 and 5-HT2 receptors, strongly inhibited both the 5-HT syndrome and the head twitch responses in all five strains. [3H]5-HT and [3H]ketanserin binding in the frontal cortex of the five strains of mice was also studied. The number of [3H]5-HT binding sites did not differ among the five strains of mice although there was a noticeable difference in the number of [3H]ketanserin binding sites. These results suggest that the 5-HT syndrome and the head twitch responses induced by tryptamine are linked separately with the 5-HT1 and 5-HT2 receptors, respectively. The strain differences in the tryptamine-induced 5-HT syndrome can be explained by the different levels of brain tryptamine. The differences in the head twitch responses in the mice are probably derived from the differences in the 5-HT2 receptor binding sites in the brain and the content of brain tryptamine.

Animals↗
PubMed1987

Hypothermia induced in mice by intracerebroventricular injection of tryptamine: involvement of the 5-HT1 receptor.

The effect on the body temperature of mice of tryptamine administered by intracerebroventricular (i.c.v.) injection was studied. Tryptamine given i.c.v. produced a significant hypothermia above a dosage of 5 nmol. The hypothermic effect of tryptamine was inhibited by methysergide whereas ketanserin and p-chlorophenylalanine did not affect it. These data demonstrate that the hypothermia induced by tryptamine i.c.v. is produced by direct activation of the 5-HT1 receptor.

Animals↗
PubMed1987

Immunohistochemical study on the distribution of neuron-specific enolase- and peptide-containing nerves in the omasum of cattle.

The distribution of nerves containing immunoreactivity for substance P (SP), vasoactive intestinal polypeptide (VIP), leucine-enkephalin (LENK), and gastrin-releasing polypeptide (GRP) in the margin of the reticulo-omasal orifice, omasum, and omasal pillar of calves and cows was studied by immunohistochemistry. The general distribution of nerves was determined by means of neuron-specific enolase (NSE) antiserum and then compared to the distribution of immunoreactive (IR) nerves stained for the four peptides. Marked differences in the distribution of immunoreactive nerves were associated with age and the segment examined. SP-IR fibers were abundant in the musculature of the ungulate papillae at the reticulo-omasal orifice and in the smooth muscle of the omasal leaves, moderately dense in the omasal pillar, and low in density in the inner muscle layer of the reticulo-omasal orifice and in the muscle of the omasal wall. In order of decreasing abundance, the cell bodies of SP-IR nerves were found at the reticulo-omasal orifice, in the omasal wall, and in the omasal pillar. LENK-IR fibers, though less abundant, showed a pattern of distribution that was similar to that of SP-IR fibers. Nerve cell bodies showing weak immunoreactivity for LENK were detected rarely. Abundant VIP-IR fibers were present in the inner muscle layer of the reticulo-omasal orifice and in the omasal wall, while moderate numbers were seen in the omasal pillar: they were low in density in the ungulate papillae and omasal leaves. Cell bodies of VIP-IR nerves decreased in number through the omasum, reticulo-omasal orifice, and omasal pillar. The distribution of GRP-IR nerve fibers was similar to that of VIP-IR fibers, although GRP-IR fibers were less abundant. Nerve cell bodies showing weak immunoreactivity for GRP were detected rarely. The individual distribution of peptide-IR nerves was similar in the calf and cow, but immunoreactive nerves were far more abundant in the calf. The present study provides valuable information for discussion of the possible role of nerves in the regulation of omasal function.

Animals↗
PubMed1987

Serotonin-storing cells of the chicken duodenum: light, fluorescence and electron microscopy, and immunohistochemistry.

In an attempt to identify duodenal endocrine cells emitting formaldehyde-induced fluorescence (FIF), chicken duodena were studied by combined fluorescence, ultrastructural, silver impregnation and immunohistochemical methods in the same or consecutive sections. Our results show that: (1) Almost all the cells emitting yellow fluorescence by both the Falck-Hillarp and the Furness methods exhibit an immunohistochemical reaction with serotonin (5-HT) antiserum. (2) Almost all cells radiating yellow fluorescence by the Furness method stain with toluidine blue in Epon-embedded sections, but, by high-voltage electron microscopy, can be subdivided into two types of cell containing either small round or polymorphous types of granules. (3) In the sections from which resin had been removed, all the cells emitting yellow FIF show argentaffinity by the Singh method, but not all cells display argyrophilia with the Grimelius method. (4) Cells exhibiting both argyrophil and argentaffin reactions in deresined serial sections are also separated into two types of cell, containing either small spherical or polymorphous types of granules by conventional electron microscopy in thin sections. Therefore, chicken enterochromaffin cells emit yellow FIF, store 5-HT, show both argentaffinity and argyrophilia, but are ultrastructurally classified into two types of granule-containing cells which may be related to polypeptides coexisting with 5-HT.

Animals↗
PubMed1987

Neurons of the ventral lateral geniculate nucleus of the hereditary microphthalmic rat: a Golgi study.

Neurons of the lateral part of the ventral lateral geniculate nucleus in the microphthalmic rat were examined by the Golgi-Cox method. These neurons were divided into the same three types as normal neurons. However, the number of branches and the length of primary dendrites of these neurons were fewer and shorter, and the size of their perikarya was smaller, compared with normal cases.

Animals↗
PubMed1987

The behavioural effects of intravenously administered tryptamine in mice.

The behavioural effects of intravenously administered tryptamine were examined in mice. Tryptamine in a dose greater than 15 mg/kg induced distinct head-weaving and hindlimb abduction. These behavioural syndromes appeared immediately after the injection and disappeared within 3 min. The changes in time course of the behaviour induced by tryptamine were consistent with those of the levels of tryptamine in the brain. Pretreatment with p-chlorophenylalanine, a depleter of 5-hydroxytryptamine (5-HT), failed to alter the effects of tryptamine on head-weaving or hindlimb abduction but did result in head-twitches which were never seen after tryptamine alone. Metergoline strongly antagonized the behavior induced by tryptamine. Pirenperone and haloperidol inhibited the behavioural syndrome, antagonizing the head-weaving in particular. alpha-Methyl-p-tyrosine, a depleter of dopamine, reduced the head-weaving without affecting the hindlimb abduction. These results indicate that the 5-HT syndrome induced by intravenous administration of tryptamine is due to the direct effect of tryptamine on the 5-HT receptor. Tryptamine-induced behaviour, especially head-weaving, seems to be linked with dopaminergic neurones.

Animals↗
PubMed1987

A new model of petit mal epilepsy: spontaneous spike and wave discharges in tremor rats.

A mutant rat, which was found in a colony of Kyoto:Wistar rats and genetically defined as a tremor rat (tm/tm), developed tremor of the whole body at 2 weeks of age but the tremor gradually disappeared between 6 and 8 weeks of age. The electroencephalogram (EEG) recorded using chronically implanted electrodes showed a 5-7 Hz (mostly 6 Hz) spike and wave complex synchronously in the cerebral cortex and hippocampus accompanied by absence-like seizure in all six tremor rats examined. The spike and wave complex appeared 0.8-1.9 times per minute and lasted for 1-17 s. However, normal EEG activity was observed in the intervening periods, free of absence-like seizure. Thus the tremor rat is considered to be a possible model for studying the pathogenesis and therapy of petit mal epilepsy in humans.

Animals↗
PubMed1987

An immunohistochemical study of the endocrine cells in the gastrointestinal mucosa of the Caiman latirostris.

Twelve endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, motilin, neurotensin, bovine pancreatic polypeptide (BPP), avian pancreatic polypeptide (APP), pancreatic glucagon, enteroglucagon, glicentin, secretin or cholecystokinin (CCK) were found in gastrointestinal mucosa of Caiman latirostris. Moderate numbers of enteroglucagon-immunoreactive cells, a few 5-HT-, somatostatin- and motilin-immunoreactive cells and rare pancreatic glucagon-immunoreactive cells were found in the fundic stomach. Numerous gastrin-immunoreactive cells and moderate numbers of somatostatin- and motilin-immunoreactive cells were seen in the pyloric stomach. Moderate numbers of 5-HT-, gastrin-, motilin- and enteroglucagon-immunoreactive cells, a few somatostatin-, neurotensin- and BPP-immunoreactive cells, and rare APP-, pancreatic glucagon-, glicentin-, secretin- and CCK-immunoreactive cells were observed in the proximal intestine. Moderate numbers of 5-HT-immunoreactive cells, small to moderate numbers of neurotensin- and enteroglucagon-immunoreactive cells and occasional somatostatin-, motilin- and BPP-immunoreactive cells were seen in the distal intestine. Moderate numbers of neurotensin-immunoreactive cells and a few 5-HT-immunoreactive cells were found also in the cloaca. Cells immunoreactive for gastrin releasing polypeptide, bombesin and gastric inhibitory peptide were not observed in the caiman gastrointestinal epithelium. The differences in endocrine cell types between the caiman and alligator are discussed in terms of their topographic distribution.

Alligators and Crocodiles↗
PubMed1987

Histological and immunohistochemical study on ontogeny of the endocrine cells in the quail gizzard.

The pre- and post-hatching development and differentiation of the endocrine cells in quail gizzard were examined histologically and immunohistochemically. A total of 158 heads (from 5th d of incubation to adult) were used in this study. The formation of gizzard tubular glands began from 11th d of incubation. 8 kinds of endocrine cells, argyrophil cells, and gastrin releasing polypeptide (GRP)-, 5-hydroxytryptamine (5-HT)-, somatostatin-, glucagon-, avian pancreatic polypeptide (APP)-, neurotensin-, and gastrin-immunoreactive cells were detected in the gizzard. These endocrine cells began to appear from 10th d of incubation. Argyrophil cells and GRP-immunoreactive cells in the gizzard were increased with age. Other kinds of immunoreactive cells were found rarely and irregularly, and some of them were found transitory in the embryonic stage.

Animals↗
PubMed1987

Immunocytochemical demonstration of gastric endocrine cells in the stomach gland patch of the koala, Phascolarctos cinerus.

The relative frequency and topographical distribution of endocrine cells containing gut hormones were studied by immunocytochemistry in the stomach gland patch of the koala. Numerous somatostatin- and a moderate number of bovine pancreatic polypeptide-immunoreactive cells were found primarily in the lower two-thirds of the oxyntic glands. 5-hydroxytryptamine-immunoreactive cells were few in number and scattered throughout these glands. Glucagon-immunoreactive cells were observed only rarely and then were confined to the basal region of the oxyntic glands.

Animals↗
PubMed1987

An immunohistochemical survey of gastric proteinase (pepsinogen and prochymosin)-containing cells in the stomach of the developing opossum (Didelphis virginiana).

Cells immunoreactive to antisera of bovine pepsinogen and prochymosin are seen in the oxyntic glands but not the pyloric or cardiac glands of the opossum. Immunoreactivities to pepsinogen and prochymosin occur within the same cell and are restricted to an undifferentiated cell type prior to weaning. The undifferentiated cells producing these gastric proteinases decrease in number until just prior to weaning and disappear with the appearance of chief cells. Thereafter, immunoreactivities to both gastric proteinases are seen primarily in chief cells.

Animals↗
PubMed1987

Distribution of methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves in the forestomach of cattle.

The distribution of methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves in the forestomach of calves and cows was studied, using immunohistochemical methods. Methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive nerves were found in all regions of the bovine forestomach. Cell bodies were found mainly in myenteric ganglia, and nerve fibers were found principally in muscular layers. Nerve fibers and ganglia were concentrated in the lips of the reticular groove, but were least numerous in ruminal and omasal walls. The reduced number of immunoreactive nerves in cows, compared with the number of those in calves, was striking, especially in the lips of the reticular groove and the omasal leaves. Results may indicate that the importance of methionine-enkephalin-Arg6-Gly7-Leu8-containing nerves in the physiologic regulation of the forestomach of the calf is different from that of the cow.

Aging↗