[Histamine H1 receptors modulate the discharge activities of inspiratory neurons in the medial region of neonatal rat nucleus retrofacialis ex vivo].
OBJECTIVE
To investigate the role of histamine H1 receptors in modulating the discharge activities of the inspiratory neurons in the nucleus retrofacialis of neonatal rats.


METHODS
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.


RESULTS
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.


CONCLUSIONS
H1 receptors play an excitatory role in the modulation of the discharge activities of the inspiratory neurons in neonatal rat brainstem slices.
Qian
Zhi-bin
ZB
Department of Physiology, Southern Medical University, Guangzhou 510515, China. qianzhibin@yahoo.cn
Qi
Ying
Y
Wu
Zhong-hai
ZH
D000818:Animals; D000831:Animals, Newborn; D055724:Electrophysiological Phenomena; D005260:Female; D066298:In Vitro Techniques; D001239:Inhalation / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011969:Receptors, Histamine H1 / Q000502:physiology*
D011969:Receptors, Histamine H1