Postnatal changes in electrophysiological properties of rat nucleus tractus solitarii neurons.

摘要: Whole-cell recordings in brainstem slices revealed postnatal changes passive and firing properties the rat caudal nucleus tractus solitarii (cNTS) neurons. Membrane potential, threshold for Na+ spike degree of sag were unchanged during development. In adult, rheobase was twice that found at birth. The input resistance decreased over period studied, while time constants declined markedly after third week. At all ages, Na(+)-dependent action potentials (APs) elicited response to depolarization. Nevertheless, AP duration gradually by 40% developmental studied. Spike amplitude smaller birth than any other ages reached a peak two weeks APs blocked application tetrodotoxin. Full replaced an initial slow oscillation young cells oscillations older cells. TTX-resistant altered cobalt (2 mM) cadmium (100 microM). afterhyperpolarization (AHP) not development, but observed less neurons adult when measured holding potential -60 mV. Neurons subdivided into one three classes based on their responses hyperpolarizing prepulse: 1) post-inhibitory rebound (PIR) cells, 2) delayed excitation (DE) 3) NON expressing neither PIR nor DE. relative proportions different cell types varied with age. mean maximum DE increased times. Voltage-clamp experiments due activation A-current. addition, three-fold increase its inactivation rate postnatally. physiological significance these results is discussed.