cAMP acts on exchange protein activated by cAMP/cAMP-regulated guanine nucleotide exchange protein to regulate transmitter release at the crayfish neuromuscular junction.
Glutamatergic synapses are highly modifiable, suiting them for key roles in processes such as learning and memory. At crayfish glutamatergic neuromuscular junctions, hyperpolarization and cyclic nucleotide-activated (HCN) ion channels mediate hormonal modulation of glutamatergic synapses and a form activity-dependent long-term facilitation (LTF) of synaptic transmission. Here, we show that a new target for cAMP, exchange protein activated by cAMP (Epac) or cAMP-regulated guanine nucleotide exchange protein, is involved in the hormonal enhancement of synaptic transmission by serotonin. Induction of LTF "tags" synapses, rendering them responsive to cAMP in an HCN-independent manner. Epac also mediates the enhancement of tagged synapses. Thus, the cAMP-dependent enhancement of transmission is mediated by two separate pathways, neither of which involves protein kinase A.
Zhong
Ning
N
Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California 9472, USA.
Zucker
Robert S
RS
D000818:Animals; D003400:Astacoidea; D020126:Brefeldin A / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D000077213:Lamotrigine; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014227:Triazines / Q000494:pharmacology
C473217:8-(4-chloro-phenylthio)-2'-O-methyladenosine-3'-5'-cyclic monophosphate; D020662:Guanine Nucleotide Exchange Factors; D007473:Ion Channels; D014227:Triazines; D005576:Colforsin; D020126:Brefeldin A; D000242:Cyclic AMP; D000077213:Lamotrigine