Influence of nitric oxide synthase inhibition on vasopressin and corticosterone secretion during water deprivation in rats.
Nitric oxide (NO) is a short-lived radical that functions as a neurotransmitter in the central nervous system and plays a physiological role in the regulation of hypothalamic-pituitary-adrenal axis and vasopressinergic axis. In the present study, we aimed to investigate the interaction between the generation of NO and vasopressin (AVP) and corticosterone release after 3 days of water deprivation in rats. Animals were previously treated with intraperitoneal (i.p.) saline or L-nitro-arginine methyl ester (L-NAME) injection. L-NAME is a nonspecific inhibitor of nitric oxide synthases. In control rats given i.p. saline or L-NAME, hypothalamic, pituitary, and plasma AVP levels and plasma corticosterone did not change from baseline levels (p>0.05). Three days of water deprivation increased significantly the corticosterone levels in plasma (p<0.01) and AVP levels in hypothalamus and plasma (p<0.01), but not in pituitary, which showed a significant decrease. These variations were concomitant with the elevation of nitrates/nitrates in plasma. L-NAME injection abolished significantly (p<0.01) the elevation of plasma corticosterone and hypothalamic AVP levels induced by water deprivation. These findings showed that in water-deprived rats, nitric oxide synthase inhibition by L-NAME inhibits corticosterone and vasopressin release, suggesting a potent stimulatory role of NO.
Mornagui
Bessem
B
Laboratoire de Physiologie des Agressions, Faculté des Sciences de Tunis, Tunis, Tunisia. bessem.mornagui@fst.rnu.tn
Rezg
Raja
R
Grissa
Abir
A
Duvareille
Monique
M
Gharib
Claude
C
Kamoun
Abdelaziz
A
El-Fazaa
Saloua
S
Gharbi
Najoua
N
D000305:Adrenal Cortex Hormones / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D001921:Brain / Q000473:pathology; D006400:Hematocrit; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000737:chemistry; D009569:Nitric Oxide / Q000737:chemistry; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D011453:Prostaglandins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014667:Vasopressins / Q000737:chemistry / Q000378:metabolism*; D014867:Water / Q000737:chemistry
D000305:Adrenal Cortex Hormones; D018377:Neurotransmitter Agents; D011453:Prostaglandins; D014867:Water; D014667:Vasopressins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester