Cloning and functional expression of a human orthologue of rat vanilloid receptor-1

Abstract

Capsaicin, resiniferatoxin, protons or heat have been shown to activate an ion channel, termed the rat vanilloid receptor-1 (rVR1), originally isolated by expression cloning for a capsaicin sensitive phenotype. Here we describe the cloning of a human vanilloid receptor-1 (hVR1) cDNA containing a 2517 bp open reading frame that encodes a protein with 92% homology to the rat vanilloid receptor-1. Oocytes or mammalian cells expressing this cDNA respond to capsaicin, pH and temperature by generating inward membrane currents. Mammalian cells transfected with human VR1 respond to capsaicin with an increase in intracellular calcium. The human VR1 has a chromosomal location of 17p13 and is expressed in human dorsal root ganglia and also at low levels throughout a wide range of CNS and peripheral tissues. Together the sequence homology, similar expression profile and functional properties confirm that the cloned cDNA represents the human orthologue of rat VR1.

Molecular targets for cannabidiol and its synthetic analogues: effect on vanilloid VR1 receptors and on the cellular uptake and enzymatic hydrolysis of anandamide

“…Over-expression of human VR1 cDNA into human hembryonic kidney (HEK) 293 cells was carried out as described previously (Hayes et al, 2000). Cells were grown as monolayers in minimum essential medium supplemented with non-essential amino acids, 10% foetal calf serum and 0.2 mM glutamine, and maintained under 95%/5% O 2 /CO 2 at 378C.…”

Effects of piperine, the pungent component of black pepper, at the human vanilloid receptor (TRPV1)

“…A human embryonic kidney cell line stably expressing human TRPV1 (hTRPV1.HEK293 cells) was generated as described previously (Hayes et al, 2000). Cells were cultured on plastic tissue culture dishes in modified Eagles's medium with Earle's salts and supplemented with 10% fetal bovine serum, nonessential amino acids and 0.2 mM L-glutamine while being maintained under 5% CO 2 at 371C.…”

“…Whole-cell patch-clamp experiments were performed according to standard methods, using an Axopatch 200B amplifier, as described previously (Hayes et al, 2000). Thick-walled borosilicate glass electrodes (GC120F10; Harvard Apparatus) having 1.5-4 MO resistance were used to record currents following drug application using an automated three-barrelled solution switching device (Warner Instruments SF-77B).…”

“…This, combined with the documented expression of TRPV1 in human sensory neurones involved in pain pathways and gastrointestinal (GI) function (Hayes et al, 2000;Ward et al, 2003), means that TRPV1 represents a good target for pharmaceutical intervention. At present, both agonist and antagonist strategies are thought to have merit for the treatment of a whole range of conditions ranging from inflammatory and neuropathic pain, to bladder dysfunction and irritable bowel syndrome (see Szallasi & Appendino (2004) for a review).…”

Is TRPV1 a useful target in respiratory diseases?

“…Caterina and co-workers cloned TRPV1 from a rat sensory neuron cDNA library and showed that the receptor is expressed in both the dorsal root (DRG) and trigeminal ganglia (TG) [24]. TRPV1 has also been cloned from humans [25], guinea pigs [26], rabbits [27], mouse mice [28] and dogs [29].…”