title: Effects of adenosine and its analogues on isolated internal carotid arteries from newborn and adult pigs.
abstract: Vasorelaxant effects of adenosine and its analogues, 5'-N-(ethylcarboxamide) adenosine (NECA), N6-(l-phenylisopropyl)-adenosine (l-PIA) and N6-cyclohexyladenosine (CHA), on isolated internal carotid arteries from newborn (1-3 days) and adult (6 months) pigs were compared. The order of vasorelaxant potencies of adenosines was: NECA greater than l-PIA greater than adenosine greater than CHA for the adult arteries and NECA greater than l-PIA greater than adenosine = CHA for the newborn arteries. Sensitivities of vessels from the newborn and mature animals to CHA and l-PIA did not differ. However, carotid arteries from the newborn pigs were less sensitive to NECA and adenosine than the adult arteries (p less than 0.05). Theophylline caused an approximately 3-fold shift to the right of the relaxant concentration-response curves to all the four adenosines on arteries from pigs of both age groups. These data suggest that adenosine is not as effective a vasodilator in the newborn as it is in the adult.
authors.affiliation: Department of Pharmacology and Therapeutics, Montreal Children's Hospital, McGill University, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Laudignon
authors.forename: J V
authors.initials: JV
authors.lastname: Aranda
authors.forename: D R
authors.initials: DR
authors.lastname: Varma
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D000831:Animals, Newborn; D002339:Carotid Arteries / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D010660:Phenylisopropyladenosine / Q000494:pharmacology*; D013552:Swine; D013806:Theophylline / Q000494:pharmacology
chemical_list: D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D013806:Theophylline; D000241:Adenosine