Neuroscience 2002 Abstract
| Presentation Number: | 830.2 |
|---|---|
| Abstract Title: | ALTERATION OF SYNAPTIC TRANSMISSION BY CANNABINOIDS IN RAT BRAINSTEM VAGAL COMPLEX. |
| Authors: |
Derbenev, A. V.*1
; Stuart, T. C.1
; Smith, B. N.1
1Dept of Cell and Molec Bio, Tulane Univ, New Orleans, LA |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - G-Protein Linked Receptors -- Other |
| Secondary Theme and Topics | Autonomic, Limbic and Other Systems<br />- Autonomic<br />-- Gastrointestinal and urogenital regulation |
| Session: |
830. G-protein linked receptors II Poster |
| Presentation Time: | Thursday, November 7, 2002 9:00 AM-10:00 AM |
| Location: | Hall A2-B3 C-36 |
| Keywords: | EPSC, IPSC, patch-clamp, nucleus tractus solitarius |
Type 1 cannabinoid receptors (CB1) bind Delta(9)–tetrahydrocannabinol and endogenously released n-acylethanolamines in various regions of the brain, including the brainstem. Cannabinoids have been shown to modify autonomic functions, including feeding behavior, but the central mechanisms underlying of these effects have not been adequately described. Immunoblots using antibodies that recognize the CB1 receptor revealed a major band of ~63 kd in both brainstem and dorsal vagal complex (DVC) tissue microdissected from brainstem slices. To determine if cannibinoids affect synaptic regulation in the caudal dorsal motor nucleus of the vagus (DMV), the effects of a cannabinoid receptor agonist on synaptic input to putative preganglionic DMV neurons were examined using whole-cell voltage-clamp recordings in brainstem slices. WIN-55,212-2 (2-10 uM), decreased spontaneous EPSC (n=14) and IPSC frequency (n=10) and attenuated synaptic responses evoked by glutamate microstimulation of nucleus tractus solitarius (NTS). The effects of the agonist on IPSCs were abolished by CB1 antagonists, but the effects on EPSCs were only partially attenuated at the same antagonist doses. In the presence of tetrodotoxin, WIN-55,212-2 diminished miniature IPSC frequency, suggesting an effect at CB1 receptors located on presynaptic GABAergic terminals. Paradoxically, miniature EPSC frequency was enhanced by the agonist. These studies indicate that WIN-55,212-2 alters synaptic inputs to vagal motor neurons in a complex fashion. Effects of cannabinoids in the DVC may depend on the role specific DMV neurons play in regulating gastric motility.
Supported by Funded by NIH grant DK56132
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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