Control of magnocellular oxytocin neurones by the region anterior and ventral to the third ventricle (AV3V region) in rats

Abstract

The involvement of the region anterior and ventral to the third ventricle (AV3V region) in the control of oxytocin release was investigated using electrical stimulation and electrolytic lesioning techniques in the rat. Electrical stimulation (0·5 mA, 50 Hz, 15–25 s) of the AV3V region of lactating rats evoked a reproducible rise in intramammary pressure equivalent to that induced by 0·25–0·5 mu. oxytocin (i.v.). Increases in circulating concentrations of oxytocin, as determined by specific radioimmunoassay, confirmed that AV3V stimulation released oxytocin in both lactating and non-lactating rats. The increases in plasma oxytocin concentration evoked by electrical stimulation of the AV3V region were dependent upon intensity and frequency of stimulation, and electrode position. A significant (PJ. Endocr. (1987) 114, 253–261