Evidence of nitric oxide and angiotensin II regulation of circulation and cutaneous drinking in Bufo marinus.
The nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (l-NAME) increased vascular resistance (VR) 10% above baseline of 3.08+/-0.08 (n=11) mmHg/mL/min at 10 mg/kg and 20% above 3.05+/-0.08 (n=9) at 50 mg/kg in anesthetized toads (Bufo marinus). Blood pressure was unaffected by either dose of L-NAME. Blood flow decreased at the higher dose of L-NAME. L-arginine (300 mg/kg) reversed the effects of L-NAME on VR and blood flow in toads treated with 10 mg/kg but not with 50 mg/kg. Injection of 50 mg/kg L-NAME into empty-bladder toads produced a 10% decrease in water uptake, J(v), resulting in a J(v) of 1,267+/-11 cm(3)/cm(2)/s x 10(-7) (n=9) compared to 1,385+/-12 (n=8) for controls. Injection of 10 microg/kg angiotensin II (ANG II) increased J(v) 15% across the pelvic patch (J(v), cm(3)/cm(2)/s x 10(-7)), resulting in a J(v) of 1,723+/-12 cm(3)/cm(2)/s x 10(-7) (n=8) compared to 1,471+/-12 (n=8) for controls. It is hypothesized that during cutaneous drinking blood flow into the capillary bed of the pelvic patch is regulated by nitric oxide and ANG II.
Rea
M S
MS
Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Parsons
R H
RH
D000327:Adsorption; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D002024:Bufo marinus / Q000502:physiology*; D005260:Female; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D010388:Pelvis / Q000098:blood supply*; D012039:Regional Blood Flow; D012879:Skin Physiological Phenomena; D014867:Water; D014882:Water-Electrolyte Balance
D014867:Water; D000804:Angiotensin II; D009569:Nitric Oxide