부산대학교 도서관

Background and purpose:Central 5-HT-containing pathways are known to be important in cardiovascular regulation and a crucial area for this regulation is the nucleus tractus solitarius (NTS), which contains many of the known 5-HT receptor subtypes. In this study the role of 5-HT1B and 5-HT1D receptors, targets for the antimigraine drugs known collectively as triptans, was examined in the NTS.Experiment approach:Extracellular recordings were made, in anaesthetized rats, from 109 NTS neurones that were excited by electrical stimulation of the vagus and drugs were applied ionophoretically to these neurones.Key results:The 5-HT1B/1D receptor agonist sumatriptan applied to 64 neurones produced a 64% reduction in the firing rate of 54 of these neurones. Ketanserin, a 5-HT1D/2A receptor antagonist, alone had little effect, but co-applied with sumatriptan significantly attenuated this inhibition, whilst co-application of the 5-HT1B receptor antagonist GR55562 resulted in potentiation of this inhibition. Sumatriptan also caused a 25% reduction in vagal afferent evoked activity as well as that caused by stimulation of cardiopulmonary afferents. In another 41 neurones the 5-HT1B receptor agonist CP-93 129 produced a doubling of the background firing rate in 31 of these neurones and a significant increase in both vagal afferent evoked activity and that evoked by cardiopulmonary afferent activation.Conclusions and implications:Activation of 5-HT1B and 5-HT1D receptors have opposing actions on NTS neurones of excitation and inhibition, respectively. As both receptors are negatively coupled to adenylate cyclase this would indicate that they have different anatomical locations within NTS.British Journal of Pharmacology (2007) 150, 987–995. doi:10.1038/sj.bjp.0707169; published online 5 March 2007 [ABSTRACT FROM AUTHOR]