Ultrasonic Analysis of Tremorine and Cold Tremor Activity in Unanesthetized Rats

C. W. Young ； M. S. Young ； M. T. Lin

《The Chinese Journal of Physiology》 40卷2期 (1997/06) Pp. 85-90

並列摘要

The role of paramedian reticular nucleus(PRN),a structure effecting sympathetic inhibition,inthe development of hypertension was investigated in young spontaneously hypertensive rats(SHR)andtwo age-matched normotensive rats,Wistar-Kyoto(WKY)and Sprague-Dawley rats(SD).Threedifferent experimental manipulations,including electrical-lesioning,sham-operated and intact control,were performed in SHR,WKY and SD rats 7 weeks after birth.In the control groups,the systolic arterialblood pressure(SABP)of SHR increased abruptly from 160 mmHg to 230 mmHg from the 6 th to 13 thweek after birth,whereas those of WKY and SD maintained a normal range of SABP.In the lesionedgroups,a hypotension and/or bradycardia was evoked by electrical stimulation to verify the location ofPRN Following the verification,a direct current was delivered to lesion the PRN in situ.The effect ofPRN lesioning on the subsequent development of hypertension was illustrated by comparing SABP inthree experimental groups of age-matched conscious SHR,WKY and SD during 8-13 weeks after birth.We found that the average SABP in the lesioned SHR was consistently elevated and was not significantlydifferent from those of the sham-operated and the control.In contrast,in the normotensive rats,therewas no significant increase in SABP within the three experimental groups,i.e.,the average SABP of thelesioned,the shamed-operated and the control group maintained a normal range.Our results supportthe contention that the hypertension of SHR developed within 6-13 weeks after birth.In addition,thesympatho-inhibitory mechanism of PRN was not directly related to the development of hypertension.

並列關鍵字

Thermogenesis ； Tremor ； Muscarinic Receptor ； Cold