Evidence for initiation of calcium spikes in C-cells of the rabbit nodose ganglion.
In Na+-free solution or in tetrodotoxin (TTX, 10(-6) M) solution, direct electrical stimulation of nodose ganglion C-cells of the rabbit elicited regenerative action potentials. The amplitude of the action potentials generated in these neurons is dependent on the external Ca2+ concentration ([Ca2+]0). These action potentials were characterized by reduced amplitude, prolonged duration, and graded responses to changes of the stimulation intensity. Either removal of [Ca2+]0 or application of organic Ca2+-blocking agents, diltiazem (10(-5) M) or verapamil (10(-5) M), abolished these action potentials. The conduction of action potentials along the axon was blocked in Na+-free solution or by application of TTX. The present results provide evidence for the initiation of Ca2+-dependent action potentials in the soma membrane of mammalian nodose ganglia, and suggest that the Ca2+ ion plays an important role in the development of action potentials in the C-cell of rabbit nodose ganglia.
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D066298:In Vitro Techniques; D008564:Membrane Potentials; D009620:Nodose Ganglion / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D012964:Sodium / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D014630:Vagus Nerve / Q000502:physiology*
D002121:Calcium Channel Blockers; D013779:Tetrodotoxin; D012964:Sodium; D002118:Calcium