title: ACTH 1-24-induced potentiation of norepinephrine contractile responses in aortic strips from spontaneously hypertensive (SH) and normotensive (WKY) rats.
abstract: Norepinephrine (NE)-induced contractile responses were less in aortic strips from SH compared to WKY rats. ACTH 1-24 potentiated NE responses in both SH and WKY aortic strips. This effect was more potent in SH aortic strips. NE-induced contractions in SH aortic strips were less sensitive to changes in external Ca2+ levels than were those of WKY aortic strips. ACTH 1-24 did not potentiate NE responses under low external Ca2+ conditions in SH aortic strips or under high external Ca2+ conditions in WKY aortic strips. The greater sensitivity of NE responses following ACTH 1-24 in SH aortic strips may imply that this peptide is modulating a mechanism related to an impaired contractility and that Ca2+ plays a key role in the observed effects.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology / Q000503:physiopathology*; D002118:Calcium / Q000494:pharmacology; D003366:Cosyntropin / Q000494:pharmacology*; D004357:Drug Synergism; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D003366:Cosyntropin; D000324:Adrenocorticotropic Hormone; D002118:Calcium; D009638:Norepinephrine