Characterization of rat transient receptor potential vanilloid I receptors lacking the N-glycosylation site N604

Whole-cell. patch-clamp recordings were performed on HEK293 cells transiently transfected with the rat (r) wild-type transient receptor potential vanilloid I (TRPVI) (rTRPVI) receptor or with a mutant that lacks the potential N-glycosylation site at position N604 (rTRPVI-N604T). Replacement of Asn by Thr (N604T) depressed the maximum of the concentration-response curve for capsaicin and decreased the EC50 value of this agonist. Further, such a manipulation modified the sensitivity to the TRPVI receptor-antagonist capsazepine and altered the dependence of the capsaicin effect on extracellular pH. Hence, glycosylation may affect the basic functional characteristics of the rTRPVI receptor channel in accordance with the knowledge that N-glycosylation may regulate ligand binding or gating properties of ionotropic neurotransmitter receptors. (c) 2005 Lippincott Williams & Wilkins.