[Desensitization to VIP by down regulation of its peptide receptors in transformed HT-29 cells of human colonic epithelium in culture].

Desensitization of VIP receptor activity (binding capacity and cAMP generation) has been evidenced in the human colonic cancer cell line HT-29 after a short term exposure of the cells in culture flasks to this neurotransmitter. This desensitization is associated with a remarkable decrease in specific binding of the purified monoiodo 125I-tyr10-VIP, as well as with a loss of the cellular cAMP response to VIP, while the cAMP generating system remains highly sensitive to forskolin. The results suggest that the desensitization of VIP receptor activity demonstrated here may participate to the short-term regulation by VIP of the intestinal cell function.