title: Cyclic AMP-mediated long-term facilitation of glycinergic transmission in developing spinal dorsal horn neurons.
abstract: cAMP is known to regulate neurotransmitter release via protein kinase A (PKA)-dependent and/or PKA-independent signal transduction pathways at a variety of central synapses. Here we report the cAMP-mediated long-lasting enhancement of glycinergic transmission in developing rat spinal substantia gelatinosa neurons. Forskolin, an adenylyl cyclase activator, elicited a long-lasting increase in the amplitude of nerve-evoked glycinergic inhibitory postsynaptic currents (IPSCs), accompanied by a long-lasting decrease in the paired-pulse ratio in immature substantia gelatinosa neurons, and this forskolin-induced increase in glycinergic IPSCs decreased with postnatal development. Forskolin also decreased the failure rate of glycinergic IPSCs evoked by minimal stimulation, and increased the frequency of glycinergic miniature IPSCs. All of these data suggest that forskolin induces the long-lasting enhancement of glycinergic transmission by increasing in the presynaptic release probability. This pre-synaptic action of forskolin was mediated by hyperpolarization and cyclic nucleotide-activated cation channels and an increase in intraterminal Ca(2+) concentration but independent of PKA. The present results suggest that cAMP-dependent signal transduction pathways represent a dynamic mechanism by which glycinergic IPSCs could potentially be modulated during postnatal development.
authors.affiliation: Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Korea.
authors.forename: In-Sun
authors.initials: IS
authors.lastname: Choi
authors.forename: Michiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Jin-Hwa
authors.initials: JH
authors.lastname: Cho
authors.forename: Hye-Mi
authors.initials: HM
authors.lastname: Park
authors.forename: Sang-Jung
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Kim
authors.forename: Jong-Ju
authors.initials: JJ
authors.lastname: Lee
authors.forename: Byung-Ju
authors.initials: BJ
authors.lastname: Choi
authors.forename: Il-Sung
authors.initials: IS
authors.lastname: Jang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D005998:Glycine / Q000502:physiology*; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D020671:Posterior Horn Cells / Q000187:drug effects / Q000254:growth & development*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000502:physiology; D013376:Substantia Gelatinosa / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D018009:Receptors, Glycine; D005576:Colforsin; D000242:Cyclic AMP; D005998:Glycine