Effects of injection of morphine into the head of the caudate nucleus on activities of neurons of the nucleus raphe magnus in rats
Zhu, B.; Liu, X.
Zhongguo Yao Li Xue Bao 5(4): 228-231
1984
ISSN/ISBN: 0253-9756 PMID: 6240896 Document Number: 224364
After microinjections of morphine (10 .mu.g/1 .mu.l on each side) into the anterior part of the head of the nucleus neurons (n = 23) was seen for 2-30 min. This effect of some neurons lasted 90-120 min. It inhibited the spontaneous firing of the majority of NRM neurons. When morphine was injected into the posterior part of the head of n. caudatum (n = 21), the firing rate and nociceptive response of the majority of neurons were not much altered. In comparison with the rats injected morphine into the anterior part, the difference was significant during 2-30 min. There was no marked difference as compared with the control group injected saline. Morphine can evidently induce a pronounced inhibitory effect upon the nociceptive response of the majority of NRM neurons only when injected into the anterior part of the head of n. caudatum.