title: Possible role of adrenoceptors in the hypothalamic paraventricular nucleus in corticotropin-releasing factor-induced sympatho-adrenomedullary outflow in rats.
abstract: OBJECTIVE
  A functional interaction between the corticotropin-releasing factor (CRF) system and noradrenergic neurons in the brain has been suggested. In the present study, we investigated the interrelationship between the central CRF-induced elevation of plasma catecholamines and adrenoceptor activation in the paraventricular nucleus of the hypothalamus (PVN) using urethane-anesthetized rats.
  
  
  METHODS
  In rats under urethane anesthesia, a femoral venous line was inserted for infusion of saline, and a femoral arterial line was inserted for collecting blood samples. Next, animals were placed in a stereotaxic apparatus for the application of test agents. Catecholamines in the plasma were extracted by alumina absorption and were assayed with high-performance liquid chromatography with electrochemical detection. Quantification of noradrenaline in rat PVN microdialysates was performed with high-performance liquid chromatography with electrochemical detection.
  
  
  RESULTS
  We showed that centrally administered CRF elevated noradrenaline release in the PVN. Furthermore, we demonstrated that microinjection of phenylephrine into the PVN induced elevation of plasma levels of adrenaline, but not of noradrenaline, whereas microinjection of isoproterenol into the PVN induced elevation of plasma levels of noradrenaline, but not of adrenaline. Bilateral blockade of adrenoceptors in the PVN revealed that phentolamine significantly suppressed the CRF-induced elevation of plasma adrenaline level, while propranolol significantly CRF-induced elevation of plasma noradrenaline level.
  
  
  CONCLUSIONS
  Our results suggest that centrally administered CRF-induced elevation of plasma levels of adrenaline and noradrenaline can be mediated via activation of α-adrenoceptors and β-adrenoceptors, respectively, in the rat PVN.
authors.affiliation: Department of Pharmacology, Graduate School of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan. Electronic address: okadas@aichi-med-u.ac.jp.
authors.forename: Shoshiro
authors.initials: S
authors.lastname: Okada
authors.affiliation: Department of Pharmacology, Graduate School of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Yamaguchi
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D018663:Adrenergic Agents / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage* / Q000378:metabolism; D004837:Epinephrine / Q000097:blood; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D010646:Phentolamine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000378:metabolism; D013566:Sympathomimetics / Q000494:pharmacology; D014520:Urethane / Q000494:pharmacology
chemical_list: D018663:Adrenergic Agents; D018686:Anesthetics, Intravenous; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D013566:Sympathomimetics; D010656:Phenylephrine; D014520:Urethane; D003346:Corticotropin-Releasing Hormone; D011433:Propranolol; D007545:Isoproterenol; D009638:Norepinephrine; D004837:Epinephrine; D010646:Phentolamine
keywords: Adrenoceptor; Corticotropin-releasing factor; Noradrenaline release; Paraventricular nucleus of the hypothalamus; Plasma catecholamines