A Cerebral Vasoconstrictive Effect of Some Adenosine Analogues. A Study of Adenosine Analogues on Local Cerebral Blood Flow and Glucose Utilisation in the Rat

Local CBF (LCBF) in the rat was determined using [ 14 C]iodoantipyrine autoradiography. Adenosine and 5'-( N-ethyl)carboxamidoadenosine in a 15-min infusion had no significant effect on LCBF, although there was a tendency to increase. N 6 -Cyclohexyladenosine (CHA) and 2-chloroadenosine (2-CADO) significantly decreased LCBF in a number of brain regions. Laser-Doppler experiments using CHA confirmed that CHA decreased CBF and that this change was monophasic. Further experiments involving the use of [ 14 C]2-deoxyglucose autoradiography showed that the unexpected vascular effects of CHA and 2-CADO were not a consequence of a decreased metabolic demand. The available data do not allow us to identify the mechanism of action by which the known vasodilators CHA and 2-CADO were able to cause a vasoconstriction and a decrease in LCBF.