Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get two FREE E-Books

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Depression: 21st Century Solutions + The Dark Side of Wheat

Abstract Title:

Combined Treatment with Morphine andΔ9-Tetrahydrocannabinol in Rhesus Monkeys: Antinociceptive Tolerance and Withdrawal.

Abstract Source:

J Pharmacol Exp Ther. 2016 May ;357(2):357-66. Epub 2016 Mar 2. PMID: 26937020

Abstract Author(s):

L R Gerak, C P France

Article Affiliation:

L R Gerak

Abstract:

Opioid receptor agonists are effective for treating pain; however, tolerance and dependence can develop with repeated use. Combining opioids with cannabinoids can enhance their analgesic potency, although it is less clear whether combined treatment alters opioid tolerance and dependence. In this study, four monkeys received 3.2 mg/kg morphine alone or in combination with 1 mg/kgΔ(9)-tetrahydrocannabinol (THC) twice daily; the antinociceptive effects (warm water tail withdrawal) of morphine, the cannabinoid receptor agonists WIN 55,212 [(R)-(1)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate] and CP 55,940 (2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl) cyclohexyl]-5-(2-methyloctan-2-yl)phenol), and the κ opioid receptor agonist U-50,488 (trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzenacetamide methanesulfonate) were examined before, during, and after treatment. To determine whether concurrent THC treatment altered morphine dependence, behavioral signs indicative of withdrawal were monitored when treatment was discontinued. Before treatment, each drug increased tail withdrawal latency to 20 seconds (maximum possible effect). During treatment, latencies did not reach 20 seconds for morphine or the cannabinoids up to doses 3- to 10-fold larger than those that were fully effective before treatment. Rightward and downward shifts in antinociceptive dose-effect curves were greater for monkeys receiving the morphine/THC combination than monkeys receiving morphine alone. When treatment was discontinued, heart rate and directly observable withdrawal signs increased, although they were generally similar in monkeys that received morphine alone or with THC. These results demonstrated that antinociceptive tolerance was greater during treatment with the combination, and although treatment conditions were sufficient to result in the development of dependence on morphine, withdrawal was not markedly altered by concurrent treatment with THC. Thus, THC can enhance some (antinociception, tolerance) but not all (dependence) effects of morphine.

Study Type : Animal Study

Print Options


Key Research Topics

Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get two FREE E-Books

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Depression: 21st Century Solutions + The Dark Side of Wheat

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2019 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.