LIGHT INDUCES CHANGES ON THE ENDOCANNABINOID SYSTEM IN ROD OUTER SEGMENTS

CHAMORRO AGUIRRE E; GAVEGLIO V; PASQUARÉ S

Buenos Aires

Workshop; Fronteras en Biociencias 3; 2018

The aim ofthe present research was to determine how the endocannabinoid system ismodulated by the illumination state of the retina. The expression and  the activity of the enzymes  related to 2-arachidonoyl glycerol (2-AG), andthe  cannabinoid receptors expression wereanalyzed in purified rod outer segments (ROS) obtained from dark-or light-adaptedretinas. Retinas were  dissected from the eyes after dark or lightadaptation. Dark-adapted bovine ROS (DROS) and bleached ROS (LROS) werepurified by a discontinuous gradient of sucrose from retinas whose optic cupwas either maintained  under dim red light or exposed to light (3000luxes) for 30 min. Diacylglycerol lipase (DAGL), Lysophosphatidate  phosphatase (LPAPase) and monoacylglycerollipase (MAGL) activities were analyzed using [3H]-diacylglycerol, [3H]oleoyl-lysophosphatidicacid, and [3H]Monoacylglycerol as substrates, respectively, DAGL (103%)and  MAGL (69%) activities were increasedin LROS respect to DROS, however the LPAPase activity was no modified by theillumination state of the retina. The expression of enzymes and receptors was detectedby Western blot. DAGLα and MAGL expression decrease while that from PLCβ1 increasedin LROS respect to DROS. CBR andGPR55  protein levels increased anddecreased, respectively,  while TRPV1remained unmodified by light. Theseresults suggest a potential role of 2-AG in phototransduction processes.