Microinjection of norepinephrine into the paraventricular nucleus of the hypothalamus stimulates corticotropin-releasing factor gene expression in conscious rats

Keiichi Itoi, Toshihiro Suda, Fumiko Tozawa, Izumi Dobashi, Nariko Ohmori, Yoko Sakai, Keishi Abe, Hiroshi Demura

Research output: Contribution to journalArticlepeer-review

Abstract

To examine the physiological effects of norepinephrine (NE) in the paraventricular nucleus of the hypothalamus (PVH) on CRF gene expression and CRF release, NE was microinjected bilaterally into the PVH of conscious rats, and kinetic studies were performed on the levels of POMC messenger RNA (mRNA) in the anterior pituitary (AP), CRF mRNA in the PVH-containing hypothalamic fragment, and plasma ACTH. Plasma ACTH levels were increased dose dependently by NE (5-50 nmol/side) injection into the PVH. They reached their peaks after 30 min and returned to the basal values after 90 min. The POMC mRNA level in the AP and hypothalamic CRF mRNA level increased significantly 90 min after NE injection and increased further after 120 min. The POMC mRNA level in the AP and hypothalamic CRF mRNA level were increased dose dependently by NE (5-50 nmol/side) after 120 min. Intracerebroventricular pretreatment with prazosin abolished completely the increase in plasma ACTH levels after intrahypothalamic NE injection, whereas pretreatment with propranolol was without significant effect. These results suggest that NE stimulates CRF gene expression in the PVH and CRF secretion into the portal circulation, thus regulating positively the hypothalamic-pituitary-adrenal axis. alpha 1-Adrenergic receptors may mediate the action of NE on CRF neurons.

Original languageEnglish
Pages (from-to)2177-2182
Number of pages6
JournalEndocrinology
Volume135
Issue number5
DOIs
Publication statusPublished - 1994

ASJC Scopus subject areas

  • Endocrinology

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