title: The effects of nifedipine on regional vascular resistance and blood flow in the spontaneously hypertensive rat.
abstract: The purpose of the study was to compare the peripheral vascular effects of the calcium blocker nifedipine (NF) in normotensive Wistar Kyoto (WKY; n = 25) rats and spontaneously hypertensive rats (SHR; n = 28). Male eighteen week old animals were anesthetized with pentobarbital (50 mg/kg i.p.) and subjected to the radioactive microsphere technique for measurement of systemic and regional hemodynamics. While NF (30 micrograms/kg i.v. or 100 micrograms/kg i.v.) was effective in reducing resistance in all sampled vascular beds of SHR and WKY, it reduced renal vascular resistance to a greater extent in the SHR than in WKY (p less than 0.025). The data suggested a similar strain-specific effect in the SHR coronary, stomach and brain vasculatures (0.12 less than p less than 0.16). By contrast, high dose NF had a preferential effect on the skeletal muscle vasculature of WKY (p less than 0.025 for blood flow, p less than 0.16 for resistance). The findings support the premise that each calcium blocker has unique regional effects that differ between SHR and WKY.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D011921:Rats, Inbred WKY / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects*; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D009543:Nifedipine