Intracellular recordings from canine intracardiac ganglion cells.

Stable transmembrane potentials were recorded from 60 canine intracardiac ganglion cells taken from 10 dogs, which had intact synaptic connections: mean resting membrane potential, input resistance and time constant were 61.5 mV, 70 M omega and 3.3 ms. Action potentials could be evoked by intrasomal current injection and by orthodromic and antidromic stimulation of interganglionic nerves. Orthodromic action potentials were initiated by excitatory postsynaptic potentials and mediated by nicotinic receptors. All action potentials could be blocked by tetrodotoxin. Intracellular labeling revealed large cell bodies and long dendritic and axonal processes. Thus, the functional and anatomical properties of canine cardiac ganglion cells and their synaptic connections can be elucidated using this preparation.