Inhibition of potassium- and ischemia-evoked [3H] D-aspartate release from isolated bovine retina by cannabinoids.

We investigated the effect of cannabinoids on potassium chloride (K+)- and ischemia-induced [3H]D-aspartate release from isolated bovine retinae. The superfusion method was employed for studies of [3H]-neurotransmitter release. Cannabinoid receptor CB1 agonists, but not the CB2 agonist JWH 015, inhibited K+ -induced [3H]D-aspartate release from bovine retinae with the following rank order of activity: anandamide > ACEA > methanandamide > WIN 55,212-2. In the ischemic model, the rank order of activity was as follows: methanandamide > ACEA > WIN 55,212-2. The CB1 receptor antagonist AM 251 blocked inhibitory responses produced by cannabinoids in both experimental conditions. In conclusion, cannabinoids inhibit evoked [3H]D-aspartate release from isolated bovine retinae via an effect on CB1 receptors.