The 5-HT 4 receptor-induced depolarization in rat hippocampal neurons is mediated by cAMP but is independent of I h

• Published in: Neuroscience letters Vol. 324; no. 1; pp. 1 - 4
• Main Authors: Chapin, Esther M., Haj-Dahmane, Samir, Torres, Gonzalo, Andrade, Rodrigo
• Format: Journal Article
• Language: English
• Published: Elsevier Ireland Ltd 2002
• Subjects: 5-Hydroxytryptamine 4 receptors; Cyclic adenosine monophosphate; Depolarization; Hippocampus; I h; Serotonin; Depolarization; I h; 5-Hydroxytryptamine 4 receptors; Serotonin; Hippocampus; Cyclic adenosine monophosphate
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(02)00113-1

Intracellular recordings were used to examine the mechanisms underlying the 5-hydroxytryptamine (5-HT) 4 receptor-mediated depolarization seen in CA1 region pyramidal cells in in vitro hippocampal brain slices. This depolarization was mimicked and occluded by administration of the membrane permeable cyclic adenosine monophosphate (cAMP) analog 8-bromo-cAMP but was unaffected by blockade of protein kinase A (PKA). These results suggest that 5-HT 4 receptors signal this depolarization through a cAMP-dependent but PKA-independent mechanism. In many cell types, 5-HT elicits a depolarization via cAMP by facilitating I h, a hyperpolarization-activated cation current. In contrast, we find no evidence for the involvement of I h in this response. Rather, this depolarization may involve a cyclic nucleotide gated channel.