论文部分内容阅读
5-HT3 receptor has been implicated in learning and memory processes.Activation of this receptor has been suggested to impair cognition whereas its inhibition is thought to facilitate memory.Gamma oscillations are proposed to play an important role in cognition and memory; however, the role of 5-HT3 receptor in gamma oscillations remains unclear.Hippocampal gamma oscillations are driven by interplay between fast-spiking parvalbumin (PV)-positive interneurons and pyramidal cells, the roles of other interneurons are poorly understood.A subpopulation of PV-negative but cholecystokinin (CCK)-positive hippocampal interneurons expresses 5-HT3 receptor.Here we investigated how 5-HT3 receptors modulate carbachol-induced gamma oscillations through these interneurons in hippocampal area CA 1.5-HT3 receptor agonist m-CPBG attenuated development of gamma oscillations.It increased afterhyperpolarization (AHP) and reduced firing frequency in 5-HT3 cells in a Ca2+-and small conductance potassium (SK)-channel-dependent manner, reduced inhibitory input to PV cells and increased but desynchronized PV cells firing, which interfered with the development of gamma oscillations.Our findings provide a novel mechanism whereby 5-HT3 interneurons modulate gamma oscillations by changing inhibition of PV interneurons, which might be involved in the modulation of cognitive functions by 5-HT3 receptors.