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K Shonai

Publications and source records attributed to K Shonai.

5 recordsLinked to original sources
PubMed1990

Distribution of catecholaminergic receptors in the rat's pancreas islet.

The effects of noradrenaline, adrenaline, isoproterenol, dopamine, apomorphine and their blockers on biphasic insulin secretion induced by 0.3% glucose were observed by means of a modified Lacy's perifusion method. Noradrenaline and adrenaline completely inhibit biphasic insulin secretion, and their effects disappeared completely after pretreatment with phentolamine. Dopamine inhibited the first phase completely and inhibited the second phase partially, and the inhibitory action of the dopamine disappeared after the pretreatment with phentolamine or propranolol. Isoproterenol had no effect on glucose-induced insulin secretion, whereas after treatment with phentolamine, isoproterenol produced a first-phase type of response. Domperidone blocked the effect of dopamine on the suppression of the first phase response. Apomorphine produced the second phase suppression slightly. It was concluded that the sympathetic alpha receptor and DA1 was distributed on the B-cells, the sympathetic beta 2 receptors on the D-cell and the DA2 on the varicosity of the sympathetic beta 2 neuron.

Animals↗
PubMed1983

[Effects of noradrenaline and isoproterenol on the insulin secretion from the rat pancreas perfused isolatedly in situ].

Effects of noradrenaline and isoproterenol on insulin secretion in rat pancreas have been studied by means of the in situ perfusion method described previously. Noradrenaline: The insulin secretion from the rat pancreas perfused with the high glucose buffer decreases after the administration of 1 microgram/0.1 ml of noradrenaline into the perfusion fluid. These noradrenaline-induced hyposecretions can be reversed by pretreatment with phentolamine (10 micrograms/ml), while they are potentiated after propranolol (10 micrograms/ml) pretreatment. Isoproterenol: The insulin secretion from the rat pancreas perfused with the same buffer increases after the administration of 1 microgram/0.1 ml of isoproterenol into the perfusion fluid. These isoproterenol-induced hypersecretions are found to be potentiated after pretreatment with phentolamine or propranolol, and atropine (100 micrograms/ml) pretreatment does not produce any changes in the isoproterenol-induced hypersecretion. These results suggest that the beta-receptors on the B-cells stimulate the insulin secretion and the beta-receptors on the D-cells decrease them. This communication gives a short discussion of whether alpha-receptors may be on D-cells or not.

Animals↗