Activation of recombinant human TRPV1 receptors expressed in SH-SY5Y human neuroblastoma cells increases [Ca²⁺]i, initiates neurotransmitter release and promotes delayed cell death

• Published in: Journal of neurochemistry 2007-08, Vol.102 (3), p.801-811
• Main Authors: Lam, Patricia M.W, Hainsworth, Atticus H, Smith, Graham D, Owen, Davina E, Davies, James, Lambert, David G
• Format: Article
• Language: English
• Subjects: Biochemistry; cell death; Gene expression; intracellular Ca; intracellular Ca2; neuronal TRPV1 expression system; Neurons; Neurotransmitters; noradrenaline release; vanilloids
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2007.04569.x

The transient receptor potential (TRP) vanilloid receptor subtype 1 (TRPV1) is a ligand-gated, Ca²⁺-permeable ion channel in the TRP superfamily of channels. We report the establishment of the first neuronal model expressing recombinant human TRPV1 (SH-SY5YhTRPV₁). SH-SY5Y human neuroblastoma cells were stably transfected with hTRPV1 using the Amaxa Biosystem (hTRPV1 in pIREShyg2 with hygromycin selection). Capsaicin, olvanil, resiniferatoxin and the endocannabinoid anandamide increased [Ca²⁺]i with potency (EC₅₀) values of 2.9 nmol/L, 34.7 nmol/L, 0.9 nmol/L and 4.6 μmol/L, respectively. The putative endovanilloid N-arachidonoyl-dopamine increased [Ca²⁺]i but this response did not reach a maximum. Capsaicin, anandamide, resiniferatoxin and olvanil mediated increases in [Ca²⁺]i were inhibited by the TRPV1 antagonists capsazepine and iodo-resiniferatoxin with potencies (KB) of ~70 nmol/L and 2 nmol/L, respectively. Capsaicin stimulated the release of pre-labelled [³H]noradrenaline from monolayers of SH-SY5YhTRPV₁ cells with an EC₅₀ of 0.6 nmol/L indicating amplification between [Ca²⁺]i and release. In a perfusion system, we simultaneously measured [³H]noradrenaline release and [Ca²⁺]i and observed that increased [Ca²⁺]i preceded transmitter release. Capsaicin treatment also produced a cytotoxic response (EC₅₀ 155 nmol/L) that was antagonist-sensitive and mirrored the [Ca²⁺]I response. This model displays pharmacology consistent with TRPV1 heterologously expressed in standard non-neuronal cells and native neuronal cultures. The advantage of SH-SY5YhTRPV₁ is the ability of hTRPV1 to couple to neuronal biochemical machinery and produce large quantities of cells.