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Updated: Jul 6, 2026
Electrophysiology on Isolated Brainstem-spinal Cord Preparations from Newborn Rodents Allows Neural Respiratory Network Output Recording
Published on: November 19, 2015
[GABA A receptor participates in respiratory enhancement induced by nikethamide in neonatal rats]
Zhi-bin Qian1, Ying Qi, Zhong-hai Wu
1Department of Physiology, Southern Medical University, Guangzhou 510515, China. qianzb@fimmu.com
Objective:
To investigate the role of GABA A receptor in nikethamide-induced respiratory enhancement in the medullary slices of neonatal rats.
Methods:
Ex vivo medullary slices of neonatal rats (1 to 3 days old) containing the medial region of the nucleus retrofacialis with the hypoglossal nerve rootlets were prepared and perfused with modified Kreb's solution to record respiration-related rhythmic discharge activity (RRDA) from the hypoglossal nerve rootlets using suction electrodes. Thirty RRDA-positive slices were randomized into 5 equal groups and perfused with nikethamide (at concentrations of 0.5, 1, 3, 5, 7, and 10 microg/ml with the optimal nikethamide concentration determined), GABA (at 10, 20, 40, and 60 micromol/ to determine the optimal concentration), 10 micromol/ bicuculline, 10 micromol/ bicuculline plus 40 micromol/L GABA, and 5 microg/ml nikethamide followed by 5 microg/ml nikethamide plus 10 micromol/ bicuculline after wash out, respectively.
Results:
Nikethamide increased RRDA at the concentrations of 0.5-7 microg/ml, and 5 microg/ml nikethamide showed the most distinct effect on the inspiratory time (TI), integral amplitude (IA), and respiratory cycle (RC). GABA at 40 micromol/ showed the most effective inhibition of RRDA in terms of TI, IA, and RC. Bicuculline at 10 micromol/ could increase the IA, TI and RC, but the combination of 10 micromol/ bicuculline and 40 micromol/ GABA had no significant effects on RRDA. Compared with nikethamide used alone, nikethamide plus bicuculline significantly increased TI and IA without affecting RC.
Conclusion:
Nikethamide can enhance RRDA of the hypoglossal nerve rootlets in the medullary slices of neonatal rats, and the effect can be partially mediated by the GABA A receptor.
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