H. Liu et al., DRINKING AND BLOOD-PRESSURE RESPONSES TO CENTRAL INJECTION OF L-NAME IN CONSCIOUS RATS, Physiology & behavior, 59(6), 1996, pp. 1137-1145
The drinking behavior and blood pressure responses to ICV administrati
on of artificial cerebrospinal fluid (aCSF) or NG-nitro-L-arginine met
hyl ester (L-NAME, 10, 250, or 500 mu g), an inhibitor of nitric oxide
synthase, were examined in conscious rats following either osmotic st
imulation (1.0 M NaCl, 15 ml/kg, SC) or induction of hemorrhage (0.7 m
l/min to a 20% blood volume loss). Water intake increased in all anima
ls. L-NAME at doses of 250 and 500 mu g, but not 10 mu g, significantl
y attenuated water consumption induced by both stimuli. The mean arter
ial blood pressure (MABP), which increased after osmotic stimulation,
was maintained at presser levels by 250 and 500 mu g of L-NAME, but de
creased progressively and reached basal levels after treatment with aC
SF and the lowest dose of L-NAME (i.e., 10 mu g). Hemorrhage significa
ntly decreased MABP in all rats. The fall in blood pressure associated
with hemorrhage returned to control levels in animals treated with 25
0 and 500 mu g of L-NAME but not in those treated with aCSF or 10 mu g
of L-NAME. These results indicate that nitric oxide is involved in th
e regulation of drinking behavior and may play an important role in th
e central control of blood pressure during osmotic stimulation and hyp
otensive hemorrhage.