Mechanism of presynaptic inhibition by neuropeptide Y at sympathetic nerve terminals.
Calcium influx through voltage-sensitive Ca2+ channels is the normal physiological stimulus for the activity-dependent release of neurotransmitters at synaptic contacts. It has been postulated that presynaptic inhibition of transmitter release is due to a reduction in Ca2+ influx at the nerve terminal, which could result from the direct inhibition of Ca2+ channels. Neuropeptide Y and noradrenaline act as cotransmitters at many sympathetic synapses. Both of these substances produce presynaptic inhibition and can inhibit Ca2+ currents in the soma of sympathetic neurons. Here we provide direct evidence that presynaptic inhibition produced by neuropeptide Y at sympathetic nerve terminals is associated with a reduction in Ca2+ influx and that this is due to the selective inhibition of neuronal N-type Ca2+ channels.
Toth
P T
PT
Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois 60637.
Bindokas
V P
VP
Bleakman
D
D
Colmers
W F
WF
Miller
R J
RJ
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D005728:Ganglia, Sympathetic / Q000166:cytology; D009411:Nerve Endings / Q000187:drug effects / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009478:Neuropeptide Y / Q000502:physiology*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D020866:omega-Conotoxin GVIA
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009478:Neuropeptide Y; D010455:Peptides; D020866:omega-Conotoxin GVIA