The purpose of the work was to study whether SM was involved in the descending inhibitory effects of NRM on nociceptive response. The cxperiments were carried out on rats. Results were as follows: 1. The influence of single and short train stimulating SM or motor areal(MI) on 55 neurons of NRM were observed. Of 55 neurons

29 units showedthe excitatory response to noxious stimulation

12 units the inhibitory respon-se and 14 units without obvious changes. During stimulation of SM with sin-gle and short train pulse for 55 neurons or MI for 10 neurons

a few unitswere activated (10/55 or 2/10)

only one unit 'were inhibited

most of themshowed no obvious changes.