Effects of calcitonin gene-related peptide on synaptic acetylcholine receptor-channels in rat muscle fibres.
Cultured myotubes and freshly dissociated muscle fibres from adult rats were exposed to calcitonin gene-related peptide (CGRP) and studied by patch-clamp recording during the peptide-induced maximal accumulation of cellular cyclic AMP (cAMP). Acetylcholine receptor- (AChR-) channel properties in myotubes were not modified by the presence of CGRP (10(-7) M). The peptide, applied to the non-patched membrane, significantly increased the variance of the AChR-channel amplitude distribution at the synaptic region of muscle fibres, and three classes of AChR-channels were resolved immediately after peptide application. AChR-channels at extrasynaptic regions of fibres from denervated muscles were unaffected by CGRP. It is suggested that CGRP may regulate the synaptic AChR-channel conductance through second messenger systems.
Eusebi
F
F
Istituto di Istologia ed Embriologia generale, University of Rome, Italy.
Farini
D
D
Grassi
F
F
Monaco
L
L
Ruzzier
F
F
D000818:Animals; D002116:Calcitonin / Q000494:pharmacology*; D015740:Calcitonin Gene-Related Peptide; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D009121:Muscle Denervation; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
D007473:Ion Channels; D009479:Neuropeptides; D011950:Receptors, Cholinergic; D002116:Calcitonin; D000242:Cyclic AMP; D015740:Calcitonin Gene-Related Peptide