Restraint stress enhances excitatory but not inhibitory synaptic transmission in the paraventricular hypothalamic nucleus of the rat

The paraventricular nucleus of the hypothalamus (PVN) is the main regulatory center of the hypothalamic-pituitary-adrenal (HPA) axis. One important function of PVN neurosecretory neurons is the release of corticotropin releasing hormone (CRH) to the pituitary gland. This study was aimed at establishing the effects of restraint stress on GABAergic and glutamatergic inputs to parvocellular neurons of the PVN. Male adult rats were subjected to restraint in metal tubes lasting for 10 min, 2 times daily (repeated for 3 consecutive days). Whole-cell recording were performed from parvocellular neurons. Spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded from cells which were voltage clamped at 0 mV and spontaneous excitatory postsynaptic currents (sEPSCs) were recorded at −76 mV. The amplitude and the frequency of sIPSCs and sEPSCs were measured. Restraint stress resulted in an increase in the frequency of sEPSCs while the amplitude of sEPSCs was not altered. Also the parameters characterizing sIPSCs remained unaltered. Thus, restraint stress selectively enhances excitatory input to the paraventricular nucleus of the rat, most likely via a presynaptic mechanism. Support: POIG 01.01.02-12-004/09-00 awarded by the European Regional Development Fund

Rekord w opracowaniu