title: Differential action of tetrodotoxin on identified leech neurons.
abstract: 1. In leech segmental ganglia, the maximum rate of depolarization of action potentials was found to depend largely on Na in the Retzius (R) cell, the mechanosensory P, N and T cells and an identifiable neuron of unknown function, the X cell. 2. Tetrodotoxin (TTX) 15 100 mumol/l had little or no effect on R and X cells. In contrast, membrane excitation in N, P and T cells was depressed in dose- and use-dependent fashion. 3. The data imply the existence of two kinds of Na channels in normal, fully differentiated leech neurons. Correlation of such differences should lead to a better understanding of how particular neurons perform different functions.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D005724:Ganglia / Q000187:drug effects / Q000502:physiology; D007865:Leeches; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology*
chemical_list: D013779:Tetrodotoxin