Effects of acute and short-term treatment with antihypertensive drugs in sinoaortic denervated rats.
Sinoaortic denervation (SAD) produced a marked increase of the systolic blood pressure (SBP). Clonidine (50 micrograms kg-1, i.p.) reduced SBP in SAD but not in sham rats. L-alpha-methyldopa (alpha-MD) (50 mg kg-1, i.p.) also induced a more effective hypotensive action in SAD than sham rats. The withdrawal of alpha-MD in SAD rats after the first treatment was not abrupt and the hypotension persisted for several days, but after the second treatment the withdrawal induced a rapid rebound hypertension. Our results suggest that SAD increases the response to the hypotensive agents. An alteration in the availability of alpha-MD to accumulate or synthesize the active metabolites was also observed after second treatment.
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000294:innervation; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology; D003714:Denervation; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008750:Methyldopa / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012849:Sinoatrial Node / Q000502:physiology; D013997:Time Factors
D000959:Antihypertensive Agents; D008750:Methyldopa; D003000:Clonidine