Nicotinic transmission in sympathetic ganglia: blockade by the snake venom neurotoxin kappa-bungarotoxin.

Kappa-bungarotoxin, a snake venom alpha-neurotoxin, blocks nicotinic transmission in chick lumbar sympathetic ganglia as well as in the rat superior cervical ganglion. Intracellular and extracellular recordings support the conclusion that the toxin has a specific action at the postsynaptic nicotinic receptors on ganglia neurons. The affinity of kappa-bungarotoxin for receptors in chick ganglia appears to be higher than that for receptors in the rat ganglia. Kappa-bungarotoxin can thus be used as a ligand for studying nicotinic receptors in a variety of neuronal preparations.