Stimulation of vasopressin by calcium microinjections in the area of the paraventricular nucleus of the hypothalamus.
The present experiments were designed to investigate the effect of local calcium application on the paraventricular nucleus (PVN) on arginine-vasopressin (AVP) release and blood pressure. A microinjection of 2 microliter of calcium gluconate 10% in the PVN elevated AVP levels to 71.6 +/- 8.7 pg/ml compared to 3.3 +/- 0.6 pg/ml in control rats receiving iso-osmolar solution of dextrose 11% (P less than 0.001), whereas peripheral plasma epinephrine and norepinephrine were normal. Despite the increase of plasma AVP levels, blood pressure and heart rate remained unchanged indicating that other unknown mechanisms counteract AVP's pressor effect. These data suggest that locally applied Ca2+ in the vasopressinergic neurons of the hypothalamus strongly stimulates the release of AVP.
D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008845:Microinjections; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D001127:Arginine Vasopressin; D002118:Calcium