Roles of N-type and Q-type Ca2+ channels in supporting hippocampal synaptic transmission.
Several types of calcium channels found in the central nervous system are possible participants in triggering neurotransmitter release. Synaptic transmission between hippocampal CA3 and CA1 neurons was mediated by N-type calcium channels, together with calcium channels whose pharmacology differs from that of L- and P-type channels but resembles that of the Q-type channel encoded by the alpha 1A subunit gene. Blockade of either population of channels strongly increased enhancement of synaptic transmission with repetitive stimuli. Even after complete blockade of N-type channels, transmission was strongly modulated by stimulation of neurotransmitter receptors or protein kinase C. These findings suggest a role for alpha 1A subunits in synaptic transmission and support the idea that neurotransmitter release may depend on multiple types of calcium channels under physiological conditions.
Wheeler
D B
DB
Department of Molecular and Cellular Physiology, Beckman Center for Molecular and Genetic Medicine, Stanford University School of Medicine, CA 94305.
Randall
A
A
Tsien
R W
RW
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D010455:Peptides / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011950:Receptors, Cholinergic / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D017470:Receptors, Glutamate / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D013111:Spider Venoms / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D011950:Receptors, Cholinergic; D018080:Receptors, GABA-B; D017470:Receptors, Glutamate; D018047:Receptors, Purinergic P1; D013111:Spider Venoms; D020867:omega-Agatoxin IVA; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; D015240:Phorbol 12,13-Dibutyrate; D020866:omega-Conotoxin GVIA; D011493:Protein Kinase C