当前位置： SCI文献检索 > BIOCHEMICAL PHARMACOLOGY期刊下所有文献 > Regulation of adenylate cyclase by cannabinoid drugs. Insights based on thermodynamic studies.

Regulation of adenylate cyclase by cannabinoid drugs. Insights based on thermodynamic studies.

Abstract：

:The abilities of lipophilic cannabinoid drugs to regulate adenylate cyclase activity in neuroblastoma cell membranes were analyzed by thermodynamic studies. Arrhenius plots of hormone-stimulated adenylate cyclase activity exhibited a break point at 20 degrees. The break point was reduced to 14 degrees by benzyl alcohol, consistent with results from other laboratories that have correlated this response with the increase in membrane fluidity induced by benzyl alcohol. Because cannabinoid drugs partition into membrane lipids and alter membrane fluidity parameters in a number of model systems, it was of interest to examine the influence of delta 9-tetrahydrocannabinol and cannabidiol on enzyme activity analyzed by the Arrhenius plot. delta 9-Tetrahydrocannabinol, known to inhibit adenylate cyclase, failed to decrease the transition temperature either at 1 microM or at concentrations exceeding its aqueous solubility (30 microM), suggesting that delta 9-tetrahydrocannabinol could not mimic the effects observed with benzyl alcohol. In contrast, 30 microM cannabidiol, which stimulated enzyme activity slightly, decreased the Arrhenius plot break point to 17.5 degrees. The decrease in the transition temperature in response to benzyl alcohol or cannabidiol was not accompanied by a change in activation energies above or below the transition temperature. delta 9-Tetrahydrocannabinol inhibits adenylate cyclase activity via Gi as does the muscarinic agonist carbachol (Howlett et al., Mol Pharmacol 29: 307-313, 1986). Both carbachol and delta 9-tetrahydrocannabinol decreased the enthalpy and entropy of activation. The net free energy of activation at 37 degrees was increased in the presence of both of these inhibitory agonists. These data suggest that, for the entropy-driven hormone-stimulated adenylate cyclase enzyme, less disorder of the system occurs in the presence of regulators that inhibit the enzyme via Gi. In summary, thermodynamic data suggest that cannabidiol can influence adenylate cyclase by increasing membrane fluidity, but that the inhibition of adenylate cyclase by delta 9-tetrahydrocannabinol is not related to membrane fluidization.

journal_name

Biochem Pharmacol

journal_title

Biochemical pharmacology

authors

Howlett AC,Scott DK,Wilken GH

doi

10.1016/0006-2952(89)90628-x

subject

Has Abstract

pub_date

1989-10-01 00:00:00

pages

3297-304

issue

eissn

0006-2952

issn

1873-2968

pii

0006-2952(89)90628-X

journal_volume

pub_type

杂志文章

在线工具

Regulation of adenylate cyclase by cannabinoid drugs. Insights based on thermodynamic studies.