Neuroscience 2004 Abstract
| Presentation Number: | 317.8 |
|---|---|
| Abstract Title: | Interactions and localization of neuropeptide Y and cannabinoids within the hypothalamus of the rat. |
| Authors: |
Gamber, K. M.*1
; Zahm, D. S.1
; Macarthur, H.1
; Westfall, T. C.1
1Pharmacological and Physiological Sci., St. Louis Univ., Saint Louis, MO |
| Primary Theme and Topics |
Homeostatic and Neuroendocrine Systems - Regulation of Food Intake and Body Weight -- Neuropeptide regulators |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Neurotransmitters<br />-- Cannabinoids |
| Session: |
317. Neuropeptides: NPY and POMC Poster |
| Presentation Time: | Sunday, October 24, 2004 4:00 PM-5:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # DD20 |
| Keywords: | FEEDING, IMMUNOHISTOCHEMISTRY, NEUROTRANSMITTER RELEASE, OBESITY |
The orexigenic properties of neuropeptide Y (NPY) have been well established within the hypothalamus. This activity is localized specifically in pathways emerging from the arcuate nucleus (ARC) and projecting to the paraventricular nucleus (PVN), lateral hypothalamus (LH), dorsomedial hypothalamus (DMH), and ventromedial hypothalamus (VMH). The orexigenic effects of cannabinoids have also been well established. Both exogenous (as the psychoactive constituents found in marijuana) and endogenous (as the arachidonic acid derivative anandamide) forms of cannabinoids have been shown to produce appetite-stimulating effects. We have previously shown that the cannabinoid agonist CP55,940 enhanced the KCl-evoked release of NPY from rat hypothalamic explants, an effect that is blocked by the cannabinoid antagonist AM251. These findings suggest the modulation of NPY release as a potential mechanism by which cannabinoids exert their orexigenic effects.
We have further investigated the interactions between cannabinoids and NPY. Here, we show that the endogenous cannabinoid anandamide augments the release of NPY from hypothalamic explants. Furthermore, the sole application of the cannabinoid receptor antagonist AM251 inhibits the release of NPY. This suggests that endogenous cannabinoids physiologically modulate NPY release in the hypothalamus. Using immunohistochemistry we have established that CB1 receptors and NPY-ir are present in the same hypothalamic nuclei although, on the basis of double-labeling studies, not co-localized in the same neurons.
We have further investigated the interactions between cannabinoids and NPY. Here, we show that the endogenous cannabinoid anandamide augments the release of NPY from hypothalamic explants. Furthermore, the sole application of the cannabinoid receptor antagonist AM251 inhibits the release of NPY. This suggests that endogenous cannabinoids physiologically modulate NPY release in the hypothalamus. Using immunohistochemistry we have established that CB1 receptors and NPY-ir are present in the same hypothalamic nuclei although, on the basis of double-labeling studies, not co-localized in the same neurons.
Supported by USPHS Grants NHLBI-60260 and NIGMS GM08306
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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