Circulating endocannabinoid concentrations during orthostatic stress.
BACKGROUND
In animals, the endocannabinoid system is activated during hemodynamic insults and restrains blood pressure in part through sympathetic inhibition.


METHODS
We tested the hypothesis that hemodynamic stress elicited by head-up tilt testing increases systemic endocannabinoid concentrations in humans and that excessive endocannabinoid availability predisposes to presyncope.


RESULTS
With head-up tilt, 2-arachidonoylglycerol increased, whereas anandamide remained unchanged.


CONCLUSIONS
In contrast to our expectations, anandamide plasma concentration at rest was directly correlated with orthostatic tolerance, rather than intolerance.
Schroeder
Christoph
C
Franz Volhard Clinical Research Center, Helios Klinikum-Berlin and Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Batkai
Sandor
S
Engeli
Stefan
S
Tank
Jens
J
Diedrich
André
A
Luft
Friedrich C
FC
Jordan
Jens
J
D000328:Adult; D001095:Arachidonic Acids / Q000097:blood*; D001794:Blood Pressure / Q000502:physiology; D063385:Cannabinoid Receptor Modulators / Q000097:blood*; D004244:Dizziness / Q000097:blood*; D063388:Endocannabinoids; D005260:Female; D005989:Glycerides / Q000097:blood*; D006801:Humans; D008297:Male; D054971:Orthostatic Intolerance / Q000097:blood; D053284:Polyunsaturated Alkamides / Q000097:blood*; D013312:Stress, Physiological; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013575:Syncope / Q000097:blood; D018667:Tilt-Table Test
D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids; D005989:Glycerides; D053284:Polyunsaturated Alkamides; C094503:glyceryl 2-arachidonate; C078814:anandamide