Histamine H1 receptors modulate the discharge activities of inspiratory neurons in the medial region of neonatal rat nucleus retrofacialis ex vivo / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the role of histamine H1 receptors in modulating the discharge activities of the inspiratory neurons in the nucleus retrofacialis of neonatal rats.</p><p><b>METHODS</b>Brainstem slices were obtained from neonatal rats containing the medial region of the nucleus retrofacialis (mNRF) with the hypoglossal nerve (XII nerve) rootlets retained. The rhythmic discharges of the inspiratory neurons (I neurons) and activities of the XII nerve rootlets were simultaneously recorded using microelectrodes and suction electrodes, respectively. The role of H1 receptors in modulation of the discharge activities of the inspiratory neurons was investigated using the H1 receptor agonist histamine and its specific antagonist pyrilamine dissolved in modified Kreb's solution for slice perfusion.</p><p><b>RESULTS</b>Histamine shortened the respiratory cycle (RC) and expiratory time (TE) of the neurons in the brain slices, and pyrilamine produced the opposite effects. Neither histamine nor pyrilamine affected the inspiratory time (TI), integral amplitude (IA) or the peak discharge frequency (PF) of the I neurons.</p><p><b>CONCLUSION</b>H1 receptors play an excitatory role in the modulation of the discharge activities of the inspiratory neurons in neonatal rat brainstem slices.</p>