Premium
Serotonin receptors partially mediate excitation of cardiac vagal neurons in the nucleus ambiguus post hypoxia/hypercapnia
Author(s) -
Kamendi Harriet,
Mendelowitz David
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a470-d
Subject(s) - excitatory postsynaptic potential , neurotransmission , inhibitory postsynaptic potential , serotonergic , nucleus ambiguus , chemistry , neuroscience , ppads , cnqx , purinergic receptor , anesthesia , medicine , endocrinology , pharmacology , nmda receptor , ampa receptor , biology , receptor , serotonin , medulla oblongata , central nervous system
Inhibitory GABAergic and glycinergic neurotransmission to cardioinhibitory cardiac vagal neurons (CVNs) in the nucleus ambiguus increase during each inspiration, while the frequency of excitatory post‐synaptic currents (EPSCs) is unaltered. However, following hypoxia and hypercapnia (H/H) there is a recruitment of excitatory pathways to CVNs. This study tests whether some of these excitatory events are mediated by 5HT pathways and serotoninergic receptors. Spontaneous and respiratory evoked EPSCs were recorded in slices from identified CVNs before, during and after 10 minutes of H/H. Before and during H/H, EPSCs were completely blocked by CNQX and AP5, selective AMPA/kainate and NMDA receptor antagonists, respectively. However, after H/H, there was a significant increase in EPSCs during inspiratory activity. While some of these EPSCs could be blocked by the purinergic antagonist PPADS, a subset of the excitatory pathways recruited are serotoninergic since odansetron, a selective 5HT3 antagonist, abolished the remaining EPSCs evoked during recovery from H/H. The results from this study suggest that following episodes of H/H two excitatory pathways, purinergic and serotoninergic, are recruited to excite CVNs in the recovery period post H/H.