Neurokinin-1 receptors modulate the excitability of expiratory neurons in the ventral respiratory group

Abstract

We studied the role of neurokinin-1 receptors (NK1-R) on the excitability of expiratory (E) neurons (tonic discharge, ETONIC; augmenting, EAUG; decrementing, EDEC) throughout the ventral respiratory group, including Bötzinger Complex (BötC) using extracellular single-unit recording combined with pressurized picoejection in decerebrate, arterially perfused juvenile rats. Responses evoked by picoejection of the NK1-R agonist, [Sar9-Met(O2)11]- substance P (SSP) were determined before and after the selective NK1-R antagonist, CP99,994. SSP excited 20 of 35 expiratory neurons by increasing the number of action potentials per burst (+33.7 ± 6.5% of control), burst duration (+20.6 ± 7.9% of contro..