Related Experiment Video
Updated: Aug 16, 2026

In Vivo SiRNA Transfection and Gene Knockdown in Spinal Cord via Rapid Noninvasive Lumbar Intrathecal Injections in Mice
Published on: March 22, 2014
Central glucocorticoid receptors modulate the expression of spinal cannabinoid receptors induced by chronic morphine
Grewo Lim1, Shuxing Wang, Jianren Mao
1Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, 15 Parkman Street, Boston, MA 02114, USA.
Abstract:
Central cannabinoid receptors (CBRs) have been implicated in the opioid analgesic effects. However, it remains unclear as to whether the expression of central CBRs would be altered after repeated morphine exposure. Here, we show that chronic intrathecal treatment with morphine (10 microg, twice daily for 6 days) induced a time-dependent upregulation of both CB-1 and CB-2 receptors within the spinal cord dorsal horn. This morphine-induced CB-1 and CB-2 upregulation was dose-dependently attenuated by the intrathecal co-administration of morphine with the glucocorticoid receptor (GR) antagonist RU38486 (0.25, 0.5, or 2 microg). The intrathecal RU38486 treatment regimen also attenuated the development of morphine tolerance. These results indicate that the expression of spinal CBRs was altered following repeated morphine exposure and regulated by the activation of central GRs.
Related Concept Videos
Opioid Receptors: Overview
Analgesia and Pain Management
GPCRs Regulate Adenylyl Cylase Activity
Two...
CNS Stimulants: Cocaine, Amphetamines and Cannabinoids
Chemotherapy-Induced Nausea and Vomiting: Cannabinoids
Two synthetic agonists of THC,...
Opioid Analgesics: Morphine and Other Natural Cogeners

