Gabaergic Pharmacological Activity of Propofol Related Compounds as Possible Enhancers of General Anesthetics and Interaction with Membranes

REINER G; DELGADO MARIN, LETICIA; OLGUÍN, N; SÁNCHEZ-REDONDO, S; SÁNCHEZ, MARIELA; RODRÍGUEZ-FARRÉ, E; SUÑOL, C; GARCÍA D.A.

CELL BIOCHEMISTRY AND BIOPHYSICS

HUMANA PRESS INC

Lugar: Oregon; Año: 2013 vol. 67 p. 515 - 525

1085-9195

Abstract Phenol compounds, such as propofol and thymol, have been shown to act on  theGABAA receptor through interaction with specific sites of this receptor. In addition,considering the high lipophilicity of phenols, it is possible that their pharmacological activity may also be the result of the interaction of phenol molecules with the surrounding lipid molecules, modulating the supramolecular organization of the receptor environment. Thus, in the present study,we study the pharmacological activity of some propofol- and thymol-related phenols on the native GABAA receptor using primary cultures of cortical neurons and investigate the effects of these compounds on the micro viscosity of artificial membranes by means of fluorescence anisotropy. The phenol compounds analyzed in this article are carvacrol, chlorothymol, and eugenol. All compounds were able to enhance the binding of [3H]flunitrazepam with EC50 values in the micromolar range and to increase the GABA-evoked Cl- influx in a concentration-dependent manner, both effects being inhibited by the competitive GABAA antagonist bicuculline. These results strongly suggest that the phenols studied are positive allosteric modulators of thisreceptor. Chlorothymol showed a bell-type effect, reducing its positive effect at concentrations ~100 uM. The concentrations necessary to induce positive allosteric modulation of GABAA receptor were not cytotoxic. Although all compounds were able to decrease the micro viscosity of artificial membranes, chlorothymol displayed a larger effect which could explain its effects on [3H]flunitrazepam binding and on cell viability at high concentrations. Finally, it is suggestedthat these compounds may exert depressant activity on the central nervous system and potentiate the effects of general anesthetics.