[Intracellular recordings and electrophysiological properties of neurons of pancreatic ganglia in vitro].

The work was carried out to investigate electrophysiological properties of neurons of cat intrapancreatic ganglia in vitro by means of intracellular recordings. The mean value of resting membrane potential was -58.5 +/- 8.7 mV (chi +/- s chi, n = 35) with a range from -45 to 72 mV. The mean values of membrane input resistance (Rm), time constant (tau) and capacity (Cm) were 68.6 +/- 5.1M omega, 3.4 +/- 0.2 ms and 50.8 +/- 3.9pF (n = 28), respectively. When depolarizing electrotonic potentials induced by intracellular injection of depolarizing current pulses (0.05-0.5nA, 5ms) reached the threshold potential level, all of the neurons could fire action potentials. The threshold, amplitude, overshoot and duration of spikes were 19.2 +/- 0.5mV, 81.0 +/- 1.7mV, 22.6 +/- 0.9mV and 2.9 +/- 0.1ms (n = 35), respectively. The spike was followed by a prolonged after spike hyperpolarization with amplitude of 20.5 +/- 0.8mV (n = 35). In most of neurons, fast excitatory postsynaptic potentials (f-EPSP) or orthodromic action potentials were recorded during stimulation of nerve trunks attached to the intrapancreatic ganglia. The mean values of amplitude, duration of the f-EPSP and conduction velocity of the nerves were 8.9 +/- 0.7mV, 25.8 +/- 1.9ms and 0.48 +/- 0.04m/s (n = 24), respectively. The ongoing synaptic activity was observed in all of cells. Moreover, f-Epsp, was induced by acetylcholine mediated through nicotinic receptors.