Osmolality- and angiotensin-induced responses in the AV3V neurons are affected by estrogen in the ovariectomized rat.
The effect of hyperosmolality (300, 320 mosmol/kg H2O) and angiotensin II (A II, 10(-8) and 10(-6) M) was tested on a total of 64 neurons within the periventricular part of the anteroventral third ventricle (AV3V) region in brain slice preparations obtained from ovariectomized (OVX) rats with or without chronic treatment of estradiol-17 beta (E2). Hypertonic perfusion with a 320 mosmol/kg H2O but not a 300 mosmol/kg H2O medium caused a significant increase in the firing discharge rate in OVX animals. Perfusion with either hypertonic medium had no effect in E2-treated rats. The neuronal firing discharge rate of neurons in OVX rats was increased following perfusion with 10(-6) M A II, but not affected following perfusion with 10(-8) M A II. In E2-treated rats, perfusion with neither 10(-8) nor 10(-6) M A II had any effect. These data suggest a dynamic relationship between the ovarian endocrine function and the central mechanisms regulating dipsogenic behavior and/or release of vasopressin in the female rat.
Akaishi
T
T
Department of Physiology, Niigata University School of Medicine, Japan. akaishi@med.niigata-u.ac.jp
Homma
S
S
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D002552:Cerebral Ventricles / Q000166:cytology / Q000187:drug effects; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects*; D009994:Osmolar Concentration; D010052:Ovariectomy; D051381:Rats; D012462:Saline Solution, Hypertonic
D004967:Estrogens; D012462:Saline Solution, Hypertonic; D000804:Angiotensin II