V. Cârlig *, A. A. Tică *, V. A. Voicu ***, I. Șelaru **, C. Georgescu *
* Conf. Dr. Valentin Cârlig, Dr. A. Tica, Dr. C. Georgescu, Disciplina Farmacologie, Facultatea de Medicină și Farmacie Craiova
** Dr. I. Șelaru, Clinica I Obstetrică Ginecologie, Facultatea de Medicină și Farmacie Craiova
*** Prof. Dr. V. Voicu, Catedra de Toxicologie, Clinica U.M.F. București
Abstract
The receptor desensibilisation is a gradual diminution, until disappearance, of the effects, as result of a continuous stimulation of the receptors. The most known example are the β1 and B2-adrenoreceptors (β3-receptors do not generate desensibilisation). The process is realizated through two mechanisms: functional decouplation and negative regulation. The first is responsible for rapid and fine diminution of the effect and consists in: a) phosphorilation, did by β-ARK or PKA, after which, the receptor is blocked by β-arrestine or the coupling of the receptor with G protein become impossible; b) sequestration; c) palmitoilation. The negative regulation is a mechanism to protect the integrity of the cell. It appears after a longer period of strong stimulation and is realised in two ways: a) diminution of the receptor gene expression and b) stimulation of the degradation of the receptors.