A facilitatory role of vasopressin in hypoxia/hypoglycemia-induced impairment of dopamine release from rat striatal slices.
The excitatory amino acid, glutamate plays a crucial role in the pathogenesis of brain damage caused by anoxia and/or hypoglycemia. Although vasopressin (VP) also acts as an excitatory transmitter in the CNS, little is known about its effect on hypoxic and/or ischemic brain damage. In this study, we investigated the effect of arginine vasopressin (AVP) on hypoxia/hypoglycemia-induced impairment of dopamine release from striatal slices. Striatal slices were incubated in hypoxia-/hypoglycemia-inducing medium with or without AVP (0.01-1.0 microM) for 20 min. After 1-3 h of washout in normal medium, high K(+)-evoked dopamine release from the slices were examined. Hypoxia/hypoglycemia-induced decrease of striatal dopamine release was reversed by the removal of Ca2+ in the medium, but not by VP1- or VP2-receptor antagonist. In contrast, AVP potentiated the hypoxia/hypoglycemia-induced decrease of dopamine release in the striatum. This AVP-induced deterioration of the striatal response was antagonized by VP2 receptor antagonist, but not by VP1 receptor antagonist. The present results suggest that AVP may play a facilitatory role in hypoxia/hypoglycemia-induced dopamine release deficit mediated through the activation of VP2 receptor.
Ochi
M
M
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Koizumi
S
S
Shibata
S
S
Watanabe
S
S
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D007003:Hypoglycemia / Q000378:metabolism*; D002534:Hypoxia, Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin; D011188:Potassium; D004298:Dopamine