Brozek G, Zhuravin I A, Megirian D, Bures J
Institute of Physiology, 2nd Medical Faculty, Charles University, Prague, Czech Republic.
Proc Natl Acad Sci U S A. 1996 Apr 16;93(8):3325-9. doi: 10.1073/pnas.93.8.3325.
Localization of the central rhythm generator (CRG) of spontaneous consummatory licking was studied in freely moving rats by microinjection of tetrodotoxin (TTX) into the pontine reticular formation. Maximum suppression of spontaneous water consumption was elicited by TTX (1 ng) blockade of the oral part of the nucleus reticularis gigantocellularis (NRG), whereas TTX injections into more caudal or rostral locations caused significantly weaker disruption of drinking. To verify the assumption that TTX blocked the proper CRG of licking rather than some relay in its output, spontaneously drinking thirsty rats were intracranially stimulated via electrodes chronically implanted into the oral part of the NRG. Lick-synchronized stimulation (a 100-ms train of 0.1-ms-wide rectangular pulses at 100 Hz and 25-150 microA) applied during continuous licking (after eight regular consecutive licks) caused a phase shift of licks emitted after stimulus delivery. The results suggest that the stimulation has reset the CRG of licking without changing its frequency. The reset-inducing threshold current was lowest during the tongue retraction and highest during the tongue protrusion period of the lick cycle. It is concluded that the CRG of licking is located in the oral part of NRG.
通过向脑桥网状结构微量注射河豚毒素（TTX），研究了自由活动大鼠中自发 consummatory 舔舐的中央节律发生器（CRG）的定位。河豚毒素（1 ng）阻断巨细胞网状核（NRG）的口部可最大程度抑制自发饮水，而向更靠尾侧或头侧部位注射河豚毒素导致饮水干扰明显较弱。为验证河豚毒素阻断的是舔舐的合适CRG而非其输出中的某个中继这一假设，通过长期植入NRG口部的电极对自发饮水的口渴大鼠进行颅内刺激。在连续舔舐（连续八次规律舔舐后）期间施加舔舐同步刺激（100 Hz和25 - 150 μA下的100-ms 0.1-ms宽矩形脉冲串）会导致刺激传递后发出的舔舐出现相位偏移。结果表明，该刺激重置了舔舐的CRG但未改变其频率。在舔舐周期的舌回缩期间，重置诱导阈值电流最低，而在舌伸出期最高。得出结论，舔舐的CRG位于NRG的口部。
