Pot in the Periphery

Cannabis would be a great therapeutic drug for pain and appetite if it was not for the psychoactive effects. Well, the smoke is harmful too, so a pill would be nice. Marijuana acts on proteins called the cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). Stimulation of the latter does not elicit a mind-altering effect. Accordingly, researchers are trying to develop medications for pain that target only the CB2 receptor. A recent study in the journal Pain has presented some results of this research.

The researchers isolated and supported human dorsal root ganglion cells in culture. The dorsal root ganglion sends pain signals to the brain from areas outside the central nervous system (brain and spinal cord). These cells expressed CB1 and CB2 receptors as well as receptors for capsaicin. Capsaicin is used to provoke a pain response; it is the hot component of chili peppers. Addition of a drug that stimulated CB2 reduced the cellular response to capsaicin. The drug acted like morphine, but did not activate opioid receptors. Clinical trials are being planned in patients with chronic pain. Drugs that activate CB2 could be used in a number of pain conditions, such as arthritis or nerve damage.

Coming in Two Weeks…I am taking a week off. I will be back in two weeks.


Reference

1. Anand U, Otto WR, Sanchez-Herrera D, et al.
Cannabinoid receptor CB2 localisation and agonist-mediated inhibition of capsaicin responses in human sensory neurons. Pain. 2008 Sep 15;138(3):667-80. Epub 2008 Aug 9.

Coming Up In Two Weeks...I Will be back in two weeks.