Effect of theophylline on binding of delta-9-tetrahydrocannabinol with mammalian neuronal and non-neuronal membranes.

ABSTRACT

Delta-9-tetrahydrocannabinol (THC) (1.6 x 10(-6)-13.33 x 10(-6) M) binds to neuronal and non-neuronal subcellular membranes in a biphasic manner. Its binding to neuronal membranes occur in the following order synaptosome > myelin > brain microsome and brain mitochondria. Unlike brain membranes binding of delta-9-THC is greater with liver microsome than liver mitochondria. Irrespective of membranes theophylline (Th) (11.0 x 10(-6) and 550.0 x 10(-6) M) increases the binding of delta-9-THC by exposure of more number of delta-9-THC binding sites on the subcellular membranes without affecting its binding affinity. Failure of Th (11.0 x 10(-6)-550.0 x 10(-6) M) to increase the binding of delta-9-THC (1.6 x 10(-6)-13.33 x 10(-6) M) in solubilized membranes suggests the involvement of membrane lipid in the Th-induced enhancement of delta-9-THC binding.