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Title: Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat

Abstract

The central injection of neurotensin (NT) has been reported to attenuate the intake of food in the fasted animal. To determine whether endogenous norepinephrine (NE) is involved in the satiating effect of NT, the in vivo activity of NE in circumscribed sites in the hypothalamus of the unanesthetized rat was examined. Bilateral guide tubes for push-pull perfusion were implanted stereotaxically to rest permanently above one of several intended sites of perfusion, which included the paraventricular nucleus (PVN), ventromedial nucleus (VMN), and the lateral hypothalamic (LH) area. After endogenous stores of NE at a specific hypothalamic locus were radiolabeled by microinjection of 0.02-0.5 ..mu..Ci of (/sup 3/H)NE, an artificial cerebrospinal fluid was perfused at the site at a rate of 20 ..mu..l/min over successive intervals of 5.0 min. When 0.05 or 0.1 ..mu..g/..mu..l NT was added to the perfusate, the peptide served either to enhance or educe the local release of NE at 50% of the sites of perfusion. In these experiments, the circumscribed effect of NT on the characteristics of catecholamine efflux depended entirely on the state of hunger or satiety of the rat. That is, when NT was perfused in the fully satiated rat, NE release was augmented withinmore » the PVn or VMN; conversely, NE release was inhibited in the LH. in the animal fasted for 18-22 h, NT exerted an opposite effect on the activity of NE within the same anatomical loci in that the efflux of NE was enhanced in the LH but attenuated or unaffected in the PVN or VMN. Taken together, these observations provide experimental support for the view-point that NT could act as a neuromodulator of the activity of hypothalamic noradrenergic neurons that are thought to play a functional role in the regulation of food intake.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Univ. of North Carolina School of Medicine, Chapel Hill
OSTI Identifier:
6218798
Resource Type:
Journal Article
Journal Name:
Am. J. Physiol.; (United States)
Additional Journal Information:
Journal Volume: 252:1
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; HYPOTHALAMUS; PHYSIOLOGY; NEUROREGULATORS; BIOLOGICAL EFFECTS; FASTING; NORADRENALINE; PERFUSED TISSUES; RATS; TRITIUM COMPOUNDS; ADRENAL HORMONES; ANIMAL TISSUES; ANIMALS; AUTONOMIC NERVOUS SYSTEM AGENTS; BODY; BRAIN; CARDIOTONICS; CARDIOVASCULAR AGENTS; CENTRAL NERVOUS SYSTEM; DRUGS; HORMONES; LABELLED COMPOUNDS; MAMMALS; NERVOUS SYSTEM; ORGANS; RODENTS; STEROID HORMONES; SYMPATHOMIMETICS; TISSUES; VERTEBRATES; 551001* - Physiological Systems- Tracer Techniques

Citation Formats

Lee, T F, Rezvani, A H, Hepler, J R, and Myers, R D. Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat. United States: N. p., 1987. Web.
Lee, T F, Rezvani, A H, Hepler, J R, & Myers, R D. Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat. United States.
Lee, T F, Rezvani, A H, Hepler, J R, and Myers, R D. 1987. "Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat". United States.
@article{osti_6218798,
title = {Neurotensin releases norepinephrine differentially from perfused hypothalamus of sated and fasted rat},
author = {Lee, T F and Rezvani, A H and Hepler, J R and Myers, R D},
abstractNote = {The central injection of neurotensin (NT) has been reported to attenuate the intake of food in the fasted animal. To determine whether endogenous norepinephrine (NE) is involved in the satiating effect of NT, the in vivo activity of NE in circumscribed sites in the hypothalamus of the unanesthetized rat was examined. Bilateral guide tubes for push-pull perfusion were implanted stereotaxically to rest permanently above one of several intended sites of perfusion, which included the paraventricular nucleus (PVN), ventromedial nucleus (VMN), and the lateral hypothalamic (LH) area. After endogenous stores of NE at a specific hypothalamic locus were radiolabeled by microinjection of 0.02-0.5 ..mu..Ci of (/sup 3/H)NE, an artificial cerebrospinal fluid was perfused at the site at a rate of 20 ..mu..l/min over successive intervals of 5.0 min. When 0.05 or 0.1 ..mu..g/..mu..l NT was added to the perfusate, the peptide served either to enhance or educe the local release of NE at 50% of the sites of perfusion. In these experiments, the circumscribed effect of NT on the characteristics of catecholamine efflux depended entirely on the state of hunger or satiety of the rat. That is, when NT was perfused in the fully satiated rat, NE release was augmented within the PVn or VMN; conversely, NE release was inhibited in the LH. in the animal fasted for 18-22 h, NT exerted an opposite effect on the activity of NE within the same anatomical loci in that the efflux of NE was enhanced in the LH but attenuated or unaffected in the PVN or VMN. Taken together, these observations provide experimental support for the view-point that NT could act as a neuromodulator of the activity of hypothalamic noradrenergic neurons that are thought to play a functional role in the regulation of food intake.},
doi = {},
url = {https://www.osti.gov/biblio/6218798}, journal = {Am. J. Physiol.; (United States)},
number = ,
volume = 252:1,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1987},
month = {Thu Jan 01 00:00:00 EST 1987}
}