title: Age-dependent renal effects of intrarenal dopamine infusion.
abstract: Three groups of anesthetized puppies 16.4 +/- 1.2 (group I), 29.6 +/- 1.6 (group II), and 49.8 +/- 2.5 (group III) days of age were used to assess the renal response to graded doses of dopamine infusion into the renal artery. Dopamine infusion at 1 microgram X kg-1 X min-1 increased renal blood flow (RBF) from 3.61 +/- 0.31 to 4.22 +/- 0.43 ml X min-1 X g kidney wet wt-1 (P less than 0.05) only in the older puppies (group III). Glomerular filtration rate (GFR) increased in groups II and III from control values of 0.69 +/- 0.14 and 0.61 +/- 0.08 to 1.08 +/- 0.19 and 0.83 +/- 0.05 ml X min-1 X g kidney wet wt-1, respectively (P less than 0.05). However, urinary flow rate and sodium excretion were variably affected. Because dopamine is known to stimulate both alpha- and beta-adrenoceptors in addition to dopamine receptors, two additional groups of puppies 11.2 +/- 1.2 (group IV) and 72.8 +/- 2.4 (group V) days of age were studied to evaluate the renal effects of dopamine during the continuous intrarenal infusion of phentolamine and nadolol (an alpha- and a beta-adrenergic blocker, respectively). Dopamine elicited increases in RBF only in the older puppies (P less than 0.05). GFR, urinary flow rate, and sodium excretion increased in both groups; however, the magnitude of the change was greater for each parameter in the older group (P less than 0.05). These experiments suggest a maturational process for specific dopamine receptors and/or effector response, which may affect the observed age-dependent increases in RBF, GFR, and renal sodium handling.
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D004231:Diuresis / Q000187:drug effects; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D007261:Infusions, Intra-Arterial; D007668:Kidney / Q000187:drug effects*; D008297:Male; D009248:Nadolol; D009318:Natriuresis / Q000187:drug effects; D010646:Phentolamine / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000187:drug effects; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D012077:Renal Artery; D012079:Renal Circulation / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011941:Receptors, Adrenergic; D011954:Receptors, Dopamine; D009248:Nadolol; D004298:Dopamine; D010646:Phentolamine