title: Acetylcholine receptors in the ciliary ganglion and in the iris muscle of the chick: specific binding and effect on the synaptic transmission of the neurotoxin from Naja naja siamensis.
abstract: 1 A specific binding of Naja naja siamensis neurotoxin was found both in the iris and in the ciliary ganglion of the chick. 2 Naja-toxin (125 nM) caused a complete block of the iris muscle contraction induced by carbamylcholine. 3 Naja-toxin had a different effect on the two neuronal populations present in the ganglion: it blocked the synaptically evoked response of the ciliary cells, while the response of the choroid ones was only slightly reduced. The effects were the same in a wide range of concentrations (125 to 2500 nM). 4 The results obtained in the iris show the existence of an acetylcholine receptor population similar to the nicotinic receptor of the skeletal muscle. 5 In the ciliary ganglion the results confirm the existence of different acetylcholine receptors on the two cell types.
mesh_terms: D000818:Animals; D002645:Chickens; D003039:Cobra Neurotoxin Proteins / Q000378:metabolism / Q000494:pharmacology*; D004546:Elapid Venoms / Q000494:pharmacology*; D005724:Ganglia / Q000187:drug effects*; D066298:In Vitro Techniques; D007498:Iris / Q000187:drug effects* / Q000294:innervation; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D011950:Receptors, Cholinergic / Q000187:drug effects* / Q000378:metabolism; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
chemical_list: D003039:Cobra Neurotoxin Proteins; D004546:Elapid Venoms; D011950:Receptors, Cholinergic