NeuroReport

Skip Navigation LinksHome > May 15, 2000 - Volume 11 - Issue 7 > Hypoxia influences enkephalin release in rats
Neuroreport:
Neurophysiology

Hypoxia influences enkephalin release in rats

Chen, Xue‐Qun; Du, Ji‐Zeng

Collapse Box

Abstract

To investigate hypoxia effects on leucine‐enkephalin (L‐ENK) levels of median eminence (ME) of hypothalamus in rats, and the possible glucocorticoid involvement in modulation. Hypoxia was stimulated in a hypobaric chamber. L‐ENK levels were measured by specific radioimmunoassay during acute, and a comparison of L‐ENK alteration was taken for bilateral adrenalectomy (ADX) with or without a replacement of dexamethasone (DEX). Acute hypoxia 10.8% O2 for 30 min and 2 h markedly enhanced L‐ENK levels of ME from 23.99 ± 7.25 in control to 51.26 ± 16.96 (P <0.01), 53.29 ± 26.10 ng/mg protein (p <0.01), and acute hypoxia at 8.2% O2 significantly increased L‐ENK of ME to 36.76 ± 15.25 (p <0.05) and 32.09 ± 3.58 ng/mg protein (p <0.05). The increased L‐ENK was returned to normoxic level when hypoxia (10.8% O2) exposure lasted for 24 h. After ADX, 10.8% O2 hypoxia induced a sharp decline of L‐ENK in the ME, but this decline was completely reversed by treatment with DEX (500 μg/rat, i.p.). Acute hypoxia increases L‐ENK level of hypothalamic ME in rats, which may present a reduced and /or inhibited release of L‐ENK, acting through a fast negative feedback mechanism of acute hypoxia activated high circulating glucocorticoid level.

© 2000 Wolters Kluwer Health | Lippincott Williams & Wilkins

Login

Article Tools

Share

Article Level Metrics

Search for Similar Articles
You may search for similar articles that contain these same keywords or you may modify the keyword list to augment your search.