[Electrical characteristics of the sensory neurons of the medical leech]

The electrical characteristics of three types of sensory neurons (N, T and P) were determined in the leech Hirudo medicinalis. Statistically significant differences were found between the values of tau, Cs and Rs in the neurons of N- and T-types. The same parameters show the least variation coefficients. The value of time constant (tau) is 17.000-46 ms, the resistivity of the soma membrane TRs) is 19.50 kphi-cm2 in T-neurons and 35 kphi-cm2 in N-neurons. The surface of the neurons estimated by their capacitance (Cs) can be 4-10 times larger than the surface of a sphere of the same size. The possible influence of electrical characteristics of the neurons on the peculiarities of their electrical reactions is discussed.