[The effects of intrathecal clonidine in spontaneously hypertensive rats]

The relationship between intrathecal clonidine and hypertension was investigated in SHR rat and WKY rat. After the animals were given clonidine 15 micrograms into the lumbar intrathecal space, blood pressure, heart rate and respiratory rate were recorded for 60 minutes under nembutal anesthesia. Percent change of mean blood pressure was significantly larger in SHR rat than in WKY rat at 50 and 60 minutes after clonidine injection. No difference was observed in percent change of heart rate and respiratory rate. The results suggest the possibility that lumbar intrathecal clonidine injection produces greater hypotension in hypertensive subjects than in normotensive subjects.