Phasic bursting activity of paraventricular neurons is modulated by temperature and angiotensin II

1. Impulse activity of phasically firing (bursting) paraventricular neurons, which are assumed to be of the vasopressinergic type, have been extracellularly recorded in brain slices of the rat.

2. Analysis of burst patterns during temperature changes, angiotensin II application and combined application of both stimuli demonstrated that certain burst parameters are effected much stronger than the mean firing rate and also for a longer period of time.

3. The most sensitive parameter was the intraburst frequency which is considered to be the most effective parameter for increased vasopressin release.

4. These data indicate that there are functionally relevant changes in the impulse patterns which are not necessarily manifested in the mean firing rate.

Author Keywords: Hypothalamus; Paraventricular nucleus; PVN; Vasopressin; AVP; Angiotensin II; Neuronal temperature sensitivity; Osmoregulation; Phasic activity; Burst; Impulse pattern; Neuromodulation; Neuronal interactions; In vitro; Rat