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Biomedical subjects

C Yanaihara

Publications and source records attributed to C Yanaihara.

At least 91 records · Page 5Linked to original sources
PubMed1983

VIP (vasoactive intestinal polypeptide)-like immunoreactive amacrine cells in the retina of the rat.

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity was demonstrated in the rat retina, using the peroxidase anti-peroxidase (PAP) method. VIP-like immunoreactivity was observed in the cytoplasm of amacrine cells of the inner nuclear layer (INL) and their varicose processes ramifying in the inner plexiform layer (IPL). VIP-like immunoreactive amacrine cells were present in both central and peripheral retinal regions. In some sections fine ramifications of varicose processes in the IPL could be clearly traced. VIP-like immunoreactivity was detected in both 'stratified' and 'diffuse' amacrine cells. VIP-like immunoreactive amacrine cells were classified into four types.

Animals↗
PubMed1983

Comparison of the action of putative endogenous kappa-agonists, leumorphin and rimorphin in vitro.

Leumorphin and rimorphin (dynorphin B) were nearly equipotent in inhibiting the contraction of the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum and the rabbit vas deferens. Leumorphin had long duration of action in vitro after wash-out, whereas the duration of action of rimorphin was relatively shorter. These action of leumorphin and rimophin were antagonized less effectively by naloxone than by Mr2266, an antagonist relatively specific for the kappa-receptor. Rimorphin as well as leumorphin inhibits the contraction of the rabbit vas deferens which contains solely kappa-receptors. It is concluded that leumorphin and rimorphin have equipotent opioid activity and act at the kappa-receptor, like other opioid peptides derived from preproenkephalin B.

Animals↗
PubMed1983

Synthesis of porcine leumorphin and some of its biological activities.

The carboxy-terminal nonacosapeptide sequence of porcine preproenkephalin B contains the sequence of Leu-enkephalin at its amino terminus. The endogenous existence of this peptide, leumorphin, has not yet been proved. Synthesis of leumorphin was carried out by a solid-phase technique and the purity and structure of the synthetic peptide were confirmed. Synthetic porcine leumorphin exhibited a dose-dependent opiate effect (ED50 4.70 X 10(-9) M) on electrically stimulated contraction of the guinea pig ileum preparation. The potency was about 100 times as high as that of Leu-enkephalin. Leumorphin was less potent than dynorphin(1-13) (ED50 0.38 X 10(-9) M) but it was more active than beta h-endorphin (ED50 18 X 10(-9) M). The opiate activity was only partially reversed by naloxone. Intracisternal injection of synthetic leumorphin caused significant analgesia in mice (ED50 7.31 nmol/mouse). The potency was lower than that of beta h-endorphin (ED50 0.60 nmol/mouse) but higher than that of dynorphin(1-13) (ED50 16.10 nmol/mouse). Intracisternally injected leumorphin did not produce such a violent behavioral effect as did dynorphin(1-13), and it exhibited a mild sedative effect. The data supports the concept that leumorphin is a new type of opioid peptide and that the synthetic preparation will be useful for further biological and immunological studies on this peptide.

Analgesia↗
PubMed1983

Dose-response comparisons of canine plasma gastroenteropancreatic hormone responses to bombesin and the porcine gastrin-releasing peptide (GRP).

This study compares the potencies of the porcine gastrin-releasing peptide (pGRP) and bombesin, in causing elevations of canine plasma gastroenteropancreatic (GEP) levels. In the dose range 0-600 pmol . kg-1 . h-1, infusion of both peptides resulted in obvious dose-related elevations of plasma levels of gastrin, pancreatic polypeptide, enteroglucagon, immunoreactive pancreatic glucagon, and insulin. In this dose range, no significant difference in potency between the two peptides in elevating plasma levels of the above hormones was observed. The results of this study, demonstrating equimolar potency of pGRP and bombesin, are in contrast to previous studies reporting that pGRP was less potent than bombesin in causing certain bioactivities in the rat following intracranial administration of the two peptides.

Animals↗
PubMed1983

The effect of the mammalian neuropeptide, gastrin-releasing peptide (GRP), on gastrointestinal and pancreatic hormone secretion in man.

Gastrin-releasing peptide, a newly isolated mammalian peptide similar in its structure and actions to the amphibian peptide, bombesin, has recently been localized to nerves in the brain, gut and pancreas. The present study investigates its effects on gut and pancreatic peptides in man. Intravenous infusion of 0.7 and 2.9 pmol min-1 kg-1 produced significant elevation of plasma gastrin, cholecystokinin-like immunoreactivity and neurotensin. It was found also to potentiate glucose-dependent insulin secretion. Its specific location in nerve fibres in the proximal gut and pancreas and its selective effect on gastroenteropancreatic peptides may favour its role as a physiological regulatory neuropeptide.

Adult↗
PubMed1983

Immunocytochemical demonstration of PHI and its co-existence with VIP in intestinal nerves of the rat and pig.

Immunocytochemical studies of the rat and pig indicate that immunoreactivity for PHI (heptacosapeptide recently isolated by TATEMOTO and MUTT, 1981, from the porcine intestine) is located in numerous nerve fibers in the ileum and colon. Myenteric and submucosal plexuses contain abundant PHI-immunoreactive fibers. Alternate staining of adjacent sections with anti-PHI and anti-VIP sera indicates that PHI-immunoreactive nerves coincide with VIP nerves. This co-existence of both peptides in the same neurons may be accounted for by their probable sharing of a common precursor.

Animals↗
PubMed1983

Immunocytochemical demonstration of the co-storage of noradrenaline with Met-enkephalin-Arg6-Phe7 and Met-enkephalin-Arg6-Gly7-Leu8 in the carotid body chief cells of the dog.

Cellular and ultrastructural localization of catecholamines in the dog carotid body was investigated by peroxidase-antiperoxidase method for light microscopy and by protein A-colloidal gold technique for electron microscopy, and compared with that of preproenkephalin A-related opioid peptides, i.e., Met-enkephalin-Arg6-Phe7 (Met-Enk-Arg-Phe) and Met-enkephalin-Arg6-Gly7-Leu8 (Met-Enk-Arg-Gly-Leu). Immunocytochemistry at the light microscopic level using consecutive semi-thin sections of Araldite-embedded tissue showed that some 30% of the chief cells contained immunoreactive noradrenaline together with Met-Enk-Arg-Phe and Met-Enk-Arg-Gly-Leu. A considerable number of chief cells exhibited immunoreactivities representing one or two of these three kinds of substances. A few chief cells showed none of the specific immunoreactivities. Immunoreactive adrenaline was not demonstrated in any cells of the dog carotid body. At the electron microscopic level, co-existence of noradrenaline with Met-Enk-Arg-Phe or Met-Enk-Arg-Gly-Leu in the same secretory granules was shown using the double labeling protein A-colloidal gold technique. Possible interactions of catecholamines and opioid peptides deserve consideration for the understanding of the chief cell's role in the carotid body chemoreceptor.

Adrenal Medulla↗
PubMed1982

Localization of bombesin and GRP (gastrin releasing peptide) sequences in gut nerves or endocrine cells.

Five anti-gastrin releasing peptide (GRP) sera have been characterized against GRP, bombesin and related polypeptides spotted on cellulose acetate discs. Antibodies reacting with the C-terminal G-14 sequence of bombesin and the 19-27 sequence of GRP, were detected in all sera. Antibodies directed exclusively against the bombesin unrelated 1-17 sequence of GRP were found only in one serum (R-6902). With parallel immunohistochemical tests only the C-terminal immunoreactivity was detected in endocrine-paracrine cells of the chicken proventriculus, while both immunoreactivities were present in nerve fibres and a few nerve cell bodies of the mammalian gut. The distribution of GRP- and bombesin-like immunoreactive nerves in the gastric mucosa of both pyloric and oxyntic type the submucosal and myenteric plexus along the whole gastrointestinal wall and at sphincter regions is detailed.

Animals↗