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.
Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
M S
MS
Rea
R H
RH
Parsons
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