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Role of the alpha agonist activity of dobutamine in mediating cardiac output: effects of prolonged isoproterenol infusion.
J Pharmacol Exp Ther. 1987 Jun; 241(3):861-9.JP

Abstract

Hemodynamic activities of dobutamine enantiomers were studied in either control rats or those infused with isoproterenol (400 micrograms/kg/hr) for 4 days. In control animals prazosin attenuated the effects of (+/-)-dobutamine on cardiac output by approximately 50%; remaining activity was blocked by propranolol. After isoproterenol infusion (+/-)-dobutamine was less efficacious and the blocking effects of prazosin were greater than 90%. Isoproterenol infusion had no effect on (-)-dobutamine-mediated (alpha-1 adrenoceptor agonist) increases in cardiac output and these actions were blocked by prazosin. By contrast, compared to (+/-)- and (-)-dobutamine, effects of (+)-dobutamine (beta adrenoceptor agonist) on cardiac output were modest, not altered by prazosin and were blocked by propranolol; (+)-dobutamine was inactive after isoproterenol infusion. (-)-Dobutamine increased systemic vascular resistance in both control and isoproterenol infused rats, whereas (+)-dobutamine was inactive. (+/-)-Dobutamine increased systemic vascular resistance only in isoproterenol-infused rats. All increases in systemic vascular resistance were blocked by prazosin. Neither (+/-)- nor (+)-dobutamine significantly altered stroke volume. By contrast, (-)-dobutamine resulted in prazosin-sensitive increases in stroke volume in both control and isoproterenol-infused rats. In control animals, (+/-)-, (+)- and (-)-dobutamine increased heart rate in a dose-dependent manner; chronotropic effects of (-)-dobutamine were less than those of either (+/-)- or (+)-dobutamine. Chronotropic effects were not demonstrable in isoproterenol-infused animals. These data support the notion that in control rats cardiac output may be increased by either alpha or beta adrenoceptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

2885411

Citation

Hayes, J S., and N Bowling. "Role of the Alpha Agonist Activity of Dobutamine in Mediating Cardiac Output: Effects of Prolonged Isoproterenol Infusion." The Journal of Pharmacology and Experimental Therapeutics, vol. 241, no. 3, 1987, pp. 861-9.
Hayes JS, Bowling N. Role of the alpha agonist activity of dobutamine in mediating cardiac output: effects of prolonged isoproterenol infusion. J Pharmacol Exp Ther. 1987;241(3):861-9.
Hayes, J. S., & Bowling, N. (1987). Role of the alpha agonist activity of dobutamine in mediating cardiac output: effects of prolonged isoproterenol infusion. The Journal of Pharmacology and Experimental Therapeutics, 241(3), 861-9.
Hayes JS, Bowling N. Role of the Alpha Agonist Activity of Dobutamine in Mediating Cardiac Output: Effects of Prolonged Isoproterenol Infusion. J Pharmacol Exp Ther. 1987;241(3):861-9. PubMed PMID: 2885411.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Role of the alpha agonist activity of dobutamine in mediating cardiac output: effects of prolonged isoproterenol infusion. AU - Hayes,J S, AU - Bowling,N, PY - 1987/6/1/pubmed PY - 1987/6/1/medline PY - 1987/6/1/entrez SP - 861 EP - 9 JF - The Journal of pharmacology and experimental therapeutics JO - J Pharmacol Exp Ther VL - 241 IS - 3 N2 - Hemodynamic activities of dobutamine enantiomers were studied in either control rats or those infused with isoproterenol (400 micrograms/kg/hr) for 4 days. In control animals prazosin attenuated the effects of (+/-)-dobutamine on cardiac output by approximately 50%; remaining activity was blocked by propranolol. After isoproterenol infusion (+/-)-dobutamine was less efficacious and the blocking effects of prazosin were greater than 90%. Isoproterenol infusion had no effect on (-)-dobutamine-mediated (alpha-1 adrenoceptor agonist) increases in cardiac output and these actions were blocked by prazosin. By contrast, compared to (+/-)- and (-)-dobutamine, effects of (+)-dobutamine (beta adrenoceptor agonist) on cardiac output were modest, not altered by prazosin and were blocked by propranolol; (+)-dobutamine was inactive after isoproterenol infusion. (-)-Dobutamine increased systemic vascular resistance in both control and isoproterenol infused rats, whereas (+)-dobutamine was inactive. (+/-)-Dobutamine increased systemic vascular resistance only in isoproterenol-infused rats. All increases in systemic vascular resistance were blocked by prazosin. Neither (+/-)- nor (+)-dobutamine significantly altered stroke volume. By contrast, (-)-dobutamine resulted in prazosin-sensitive increases in stroke volume in both control and isoproterenol-infused rats. In control animals, (+/-)-, (+)- and (-)-dobutamine increased heart rate in a dose-dependent manner; chronotropic effects of (-)-dobutamine were less than those of either (+/-)- or (+)-dobutamine. Chronotropic effects were not demonstrable in isoproterenol-infused animals. These data support the notion that in control rats cardiac output may be increased by either alpha or beta adrenoceptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/2885411/Role_of_the_alpha_agonist_activity_of_dobutamine_in_mediating_cardiac_output:_effects_of_prolonged_isoproterenol_infusion_ L2 - https://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=2885411 DB - PRIME DP - Unbound Medicine ER -