Hi Céline. When you say alternative, do you mean to RTX? The classic method is 50 mg/kg subcutaneous capsaicin in neonates (rats), with higher doses needed for adults. I never used RTX, but I suppose in principle it could be used in a similar manner, although I would worry about collateral effects. If capsaicin is what you are looking for, I can dig up my protocol.
We have a protocol that works adapted from the publication below and I can send it to you but keep in mind that it might affect more than TRPV1: https://www.researchgate.net/publication/24309636_Resiniferatoxin_mediated_ablation_of_TRPV1_neurons_removes_TRPA1_as_well
Article Resiniferatoxin mediated ablation of TRPV1+ neurons removes ...