Ionic conductances in two types of sensory neurons in the leech, macrobdella decora

Abstract

1. 1. Ion conductances were investigated in two kinds of leech sensory neurons (p m and N 1 cells) which differ in their membrane excitability and action potential. 2. 2. In the pm cell body excitable membrane behavior is dominated by only two currents, a sodium current (i na) and a delayed rectifier (I K). 3. 3. In contrast, in the n 1 cell I Na and I K is supplemented with the presence of a transient potassium current, I A. 4. 4. A comparison between I Na and I K in the two cell types did not reveal any significant difference in activation and inactivation kinetics of either current between neurons. 5. 5. Thus, the properties and presence of the A-current in the n 1 cell and not in the P M cell may account for the functional difference in excitability of the two kinds of neurons.