Journal
JOURNAL OF PHYSIOLOGY-LONDON
Volume 559, Issue 3, Pages 923-938Publisher
WILEY
DOI: 10.1113/jphysiol.2004.067470
Keywords
-
Categories
Funding
- NIDDK NIH HHS [DK56132, R56 DK056132, R01 DK056132] Funding Source: Medline
Ask authors/readers for more resources
Cannabinoids bind central type I receptors (CBIR) and modify autonomic functions, including feeding and anti-emetic behaviours, when administered peripherally or into the dorsal vagal complex. Western blots and immunohistochemistry indicated the expression of CBIR in the rat dorsal vagal complex, and tissue polymerase chain reaction confirmed that CBIR message was made within the region. To identify a cellular substrate for the central autonomic effects of cannabinoids, whole-cell patch-clamp recordings were made in brainstem slices to determine the effects of CBIR activation on synaptic transmission to neurones of the dorsal motor nucleus of the vagus (DMV). A subset of these neurones was identified as gastric related after being labelled retrogradely from the stomach. The CB1R agonists WIN55,212-2 and anandamide decreased the frequency of spontaneous excitatory or inhibitory postsynaptic currents in a concentration-related fashion, an effect that persisted in the presence of tetrodotoxin. Paired pulse ratios of electrically evoked postsynaptic currents were also increased by WIN55,212-2. The effects of WIN55,212-2 were sensitive to the selective CB1R antagonist AM251. Cannabinoid agonist effects on synaptic input originating from neurones in the nucleus tractus solitarius (NTS) were determined by evoking activity in the NTS with local glutamate application. Excitatory and inhibitory synaptic inputs arising from the NTS were attenuated by WIN55,212-2. Our results indicate that cannabinoids inhibit transfer of synaptic information to the DMV, including that arising from the NTS, in part by acting at receptors located on presynaptic terminals contacting DMV neurones. Inhibition of synaptic input to DMV neurones is likely to contribute to the suppression of visceral motor responses by cannabinoids.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available