[Postsynaptic mechanisms of the initiation of burst activity in neuron PPa1 of Helix pomatia in response to an interneuron].

Postsynaptic mechanisms of the connection between an interneuron initiating the bursting activity in neurons RPa1 and V7 and the neurons themselves were examined. Under voltage clamp conditions a slow inward current could be recorded in these neurons after stimulation of the interneuron. A decrease of temperature reduced the speed of rise and fall of this current with a temperature coefficient about 10. The current-voltage characteristic of the slow inward current had a maximum near -65 mV. The decrease in external concentration of Na+ ions led to a decrease of its amplitude. At the maximum of this current short hyperpolarizing pulses induced outward currents instead of inward ones. It is concluded that interneuronal stimulation activate at least two types of ionic channels in the bursting neurons soma. This process, perhaps, is mediated via a chain of cytoplasmic biochemical reactions.