The role of norepinephrine and nitric oxide in activities of rat arginine vasopressin neurons in response to immune challenge.
To explore the potential role of norepinephrine (NE) and nitric oxide (NO) in activities of rat hypothalamus arginine vasopressin (AVP) neurons in response to immune challenge, we observed the effect of prazosin, an antagonist of alpha1-adrenergic receptor, and the specific nitric oxide synthase (NOS) inhibitor N(w)nitro-L-arginine-methylester (L-NAME) on the Fos expression in AVP neurons induced by systemic lipopolysaccharide (LPS) using double immunohistochemistry. Intravenous (i.v.) injection of LPS induced Fos expression in AVP neurons mainly in the hypothalamus paraventricular nucleus (PVN) and in the supraoptic nucleus (SON). The percentage of Fos-positive AVP neurons was dose-dependent. Pretreatment with prazosin (5 mg/kg) effectively suppressed the Fos expression induced by LPS (5 microg/kg), whereas L-NAME (30 mg/kg) did not influence the Fos expression in the AVP neurons induced by LPS (0.25, 0.5, 1, 5 microg/kg). Our results suggest that the activation of central AVP neurons caused by systemic LPS may be mediated by NE through alpha1-adrenergic receptors, but could not be changed by NO.
Xu
Shuang
S
Department of Physiology, School of Medicine, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
Guo
Shiyu
S
Jiang
Xinhong
X
Umezawa
Teruyasu
T
Hisamitsu
Tadashi
T
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000378:metabolism*; D002452:Cell Count / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007031:Hypothalamus / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D007150:Immunohistochemistry / Q000379:methods; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D009569:Nitric Oxide / Q000502:physiology*; D009638:Norepinephrine / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D000317:Adrenergic alpha-Antagonists; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D016760:Proto-Oncogene Proteins c-fos; D001127:Arginine Vasopressin; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester; D009638:Norepinephrine; D011224:Prazosin