新生大鼠离体延髓面神经后核内侧区微量注射GABA和BIC对呼吸节律的影响

Effects of microinjection of GABA and bicuculline into the medial area of the nucleus retrofacialis on respiratory rhythm in nconatal rat: An in vitro study

目的与方法本实验采用新生大鼠离体脑干-脊髓标本，以玻璃吸附电极记录颈4或颈5腹根（C4v或C5v）的自发节律性呼吸放电（SRRD），在延髓面神经后核内侧区（mNRF）微量注射T-氨基丁酸（GABA）及其受体拮抗剂荷包牡丹碱（BIC），观察其对C4v或C5v的SRRD的影响。结果（1）双侧微量注射10μmol／LGABA0.25μl，C4v或C5v的SRRD节律不齐，幅度下降，频率逐渐减慢至停止。（2）在对照区域（疑核尾部）双侧微量注射10μmol／LGABA0．25μl，C4v或C5v的SRRD的幅度下降，频率减慢但不停止；（3）双侧微量注射20μmol／LBIC0.25μl，C4v或C5v的SRRD频率加快，幅度略有降低:（4）预先向mNRF双侧微量注射20μmol／LBIC0.25μl，再注射10μmol／LGABA0.25μl，SRRD无明显变化。结论GABA及GABAA在mNRF呼吸节律的产生和调控中起重要作用。

In our previous works. we discovered and pointed out that the medial area of nucleus tetrofacialis (mNRF) is a bicucullinecritical site that generates the respiratory rhythm. We have recently studied the effects of microinjection of γ-aminobutyrio acid(GABA) and bicuculline (BIC) into the mNRF on the spontanous rhythmical respiratory discharge activity (SRRD) of the ventralroots C4 or C5 (C4v or C5v) in brainstem-spinal cord preparation of neonatal SD rats. The results showed that after bilateralmicroinjection of 10 μmol/L GABA 0.25 μl into mNRF, the amplitude of SRRD fell, and the rhythm of SRRD was irregular, and thefrequency of SRRD was gradually reduced till completely ceased; that after bilateral microinjection of 10 μmol/L GABA 0.25μl intocontrol area (the caudal division of nucleus ambiguous. cNA). the amplitude of SRRD fell, and the frequency of SRRD was reducedbut not ceased. that after bilateral microinjection of 20 μmol/L BIC 0.25 μl into mNRF. the amplitude of SRRD fell slightly. andthe frequency of SRRD was increased. and that bilateral microinjection of 20 umol/L BIC 0.25 μl into mNRF first. and then of 10μmol/L GABA 0.25 μl into the same site. caused no significant changes of the SRRD. It is suggested that GABA and GABA^receptor play important roles in the genesis and regulation of respiratory rh}4hm in mNRF.