Sensitive nicotinic and mixed nicotinic-muscarinic receptors in insect neurosecretory cells.
Short-term cultured dorsal unpaired median neurones from adult cockroach, Periplaneta americana, have been used to study alpha-bungarotoxin-resistant cholinergic receptors. Both acetylcholine and nicotine applied by pressure ejection to the neuronal soma induced depolarizing responses recorded with the patch-clamp technique in the whole cell recording configuration. Nicotine was more potent than acetylcholine and developed a dose-dependent biphasic depolarization including a fast and a slow component. The slow component was sensitive to alpha-bungarotoxin, d-tubocurarine, pirenzepine and gallamine, whereas the fast component was resistant to these nicotinic and muscarinic antagonists. These results demonstrate that two distinct functional receptors exist: a sensitive nicotinic and a 'mixed' (nicotinic muscarinic) receptor governing a nicotine-induced biphasic response.
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Laboratoire de Neurophysiologie, C.N.R.S. URA 611, Université d'Angers, France.
Le Corronc
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Hue
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D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D005703:Gallamine Triethiodide / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000378:metabolism; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism; D010526:Periplaneta / Q000378:metabolism*; D010890:Pirenzepine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects*; D011978:Receptors, Nicotinic / Q000187:drug effects*; D014403:Tubocurarine / Q000494:pharmacology
D002038:Bungarotoxins; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D010890:Pirenzepine; D005703:Gallamine Triethiodide; D014403:Tubocurarine