Facilitatory effect of vasopressin on the ischemic decrease of the CA1 presynaptic fiber spikes in rat hippocampal slices.
We investigated the effects of vasopressin-related neuropeptides on the hypoxia/hypoglycemia (ischemia)-induced decrease of the CA1 presynaptic potential elicited by stimulation of Schaffer collaterals in rat hippocampal slices. Treatment with arginine-vasopressin (AVP) potentiated the ischemic decrease of the CA1 presynaptic potential. In contrast, a V1 receptor antagonist produced a dose-dependent neuroprotective effect, whereas a V2 receptor antagonist had no effect. The AVP-induced decrease of the CA1 presynaptic potential was completely blocked by simultaneous application of the V1 receptor antagonist. Because AVP4-9 is regarded as the major proteolytic product of AVP in the rat brain, we examined its effect on the ischemic decrease of the CA1 presynaptic potential. Treatment with AVP4-9 produced a more marked reduction of the potential than treatment with AVP itself. The present study demonstrates that stimulation of the V1 receptor has a detrimental effect on the development of ischemic damage whereas V1 receptor blockade has a neuroprotective effect, suggesting that AVP may potentiate ischemic neuronal deficits via V1 receptor stimulation.
Tanaka
T
T
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Shishido
Y
Y
Shibata
S
S
Watanabe
S
S
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002545:Brain Ischemia / Q000503:physiopathology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000098:blood supply / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017661:Receptors, Presynaptic / Q000187:drug effects / Q000502:physiology*; D017483:Receptors, Vasopressin / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000502:physiology
D017661:Receptors, Presynaptic; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin