A Systematic Investigation of Whether Cannabinoids and Opioids Interact in the Nucleus Accumbens Shell to Differentially Impact Feeding Patterns on a Palatable Diet

Systemically administered cannabinoids and opioids have been shown to synergistically impact eating in the rat. Pharmacological manipulations of both cannabinoids and opioids in the nucleus accumbens appear to differentially impact eating. Therefore, the nucleus accumbens may be one neural location of the observed systemic effects of these neurochemical messengers. These experiments sought to investigate the effects of opioids and cannabinoids, acting in the nucleus accumbens shell, on consumption of a palatable food by determining whether blockade of CB1 receptors modulated mu-opioid stimulated feeding, and whether blockade of mu-opioid receptors impacted CB1 stimulated feeding. Additionally, these experiments sought to investigate whether co-administering opioid and cannabinoid agonists into the nucleus accumbens synergistically impacted feeding behavior. Results suggest that the mu-opioid receptor agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) impacted feeding by shifting eating to the beginning of a feeding session, as well as by increasing the total amount of food consumed across a session. There was some evidence that the CB1 receptor agonist WIN 55,212-2 shifted feeding to earlier in a session and that CB1 receptor stimulation augmented the DAMGO-induced feeding effect. Additionally, results indicated that both the mu-opioid receptor antagonist naltrexone and the CB1 receptor antagonist rimonabant blocked DAMGO-induced feeding. Taken together, these results imply that the nucleus accumbens shell may be one neural location of the observed synergistic effects of the opioid and cannabinoid systems on feeding.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2009

Author dc:creator

• Skelly, Mary

• Cannabinoids

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10339/14647

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/14647