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Effects of centrally administered orexin-B and orexin-A: a role for orexin-1 receptors in orexin-B-induced hyperactivity.
- Source :
-
Psychopharmacology . 2001, Vol. 153 Issue 2, p210. 9p. 7 Graphs. - Publication Year :
- 2001
-
Abstract
- Abstract Rationale: Orexin-A and orexin-B are hypothalamic neuropeptides derived from a 130-amino acid precursor, prepro-orexin, and are potent agonists at both the orexin-1 (OX[sub 1]) and orexin-2 (OX[sub 2]) receptors. Orexin-A has been ascribed a number of in vivo functions in the rat after intracerebroventricular (ICV) administration, including hyperphagia, neuroendocrine modulation and a role in the regulation of sleep-wake function. The in vivo role of orexin-B is not as clear. Objectives: To investigate the behavioural, endocrine and neurochemical effects of orexin-B in in-vivo tests. In a number of experiments, these effects were compared with those of orexin-A. Methods: Experiments were carried out in male, Sprague-Dawley rats with a guide cannula directed towards the lateral ventricle. The effects of orexin-B (ICV) upon grooming behaviour were compared with those of orexin-A. The effects of orexin-B upon the motor activity response to both novel and familiar environments were assessed in an automated activity monitor. Orexin-B was tested upon startle reactivity and body temperature. Further, plasma hormones and [DOPAC+ HVA]/[DA] and [5-HIAA]/[5-HT] ratios in six brain areas were measured 40 min post-orexin-B or orexin-A. Results: The clearest behavioural response to orexin-B was increased motor activity in both novel and familiar environments. Orexin-B-induced hyperactivity was blocked by an OX[sub 1] receptor antagonist, SB-334867-A, implicating OX[sub 1] receptors in this behavioural response. In common with orexin-A, orexin-B reduced plasma prolactin and failed to influence startle reactivity. However,... [ABSTRACT FROM AUTHOR]
- Subjects :
- *NEUROPEPTIDES
*AMINO acids
*SLEEP-wake cycle
Subjects
Details
- Language :
- English
- ISSN :
- 00333158
- Volume :
- 153
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Psychopharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 4693271
- Full Text :
- https://doi.org/10.1007/s002130000551