Pressor sensitivities to vasopressin, angiotensin II, or methoxamine in diabetic rats.
We investigated the pressor sensitivities to vasopressin, angiotensin II, and methoxamine of intact and ganglion-blocked rats that had been treated 21 days earlier with streptozotocin or saline. No differences in blood pressure or heart rate responses to vasopressin or angiotensin II were found between the intact groups when these peptides were administered intravenously in equimolar doses. After ganglion blockade a significant enhancement in pressor responsiveness to both vasopressin and angiotensin II was observed in the control groups, but in the streptozotocin-treated animals no enhancement in pressor sensitivity to vasopressin was found. Furthermore, although a significant augmentation of the responses to angiotensin II was observed, it was smaller than that seen in the ganglion-blocked control group. Neither group showed enhanced pressor responsiveness to methoxamine. These results indicate that the previously observed diminished contributions from endogenous vasopressin and the renin-angiotensin system to blood pressure recovery following ganglion blockade in streptozotocin-treated rats may have been due, at least in part, to diminished pressor responsiveness.
Hebden
R A
RA
Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, United Kingdom.
Bennett
T
T
Gardiner
S M
SM
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology; D002216:Captopril / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008729:Methoxamine / Q000494:pharmacology*; D010425:Pentolinium Tartrate / Q000494:pharmacology; D011311:Pressoreceptors / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood; D014667:Vasopressins / Q000494:pharmacology*
D014667:Vasopressins; D000804:Angiotensin II; D001127:Arginine Vasopressin; C025044:argipressin, beta-mercapto-beta,beta cyclopentamethylenepropionic acid(1)-; D010425:Pentolinium Tartrate; D002216:Captopril; D012083:Renin; D008729:Methoxamine