{'fraction_non_alphanumeric': 0.04708333333333333, 'fraction_numerical': 0.035416666666666666, 'mean_word_length': 4.771634615384615, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
TRPV1 Mediates The Orofacial Antinociceptive Effect of Frutalin: In Vivo and In Silico Studies

Our previous studies have shown the orofacial antinociceptive effect of frutalin (FTL) and it was suggested that FTL effect on acute orofacial pain could be mediated by TRPA1 and TRPV1. Docking study indicated that FTL strongly interacts with TRPV1. This study was conducted to investigate the relationship between TRPV1/TRPA1 channels and the orofacial antinociceptive effect of FTL. Mice (n=6/group) were pretreated with vehicle (0.9 % NaCl; 10 mL/kg; i.p.), FTL (0.5 mg/kg; i.p.), ruthenium red (TRPV1 antagonist, 3 mg/kg, s.c.) or camphor (TRPA1 antagonist, 7.6 mg/kg, s.c.) 30 min before injection (20 μL) of capsaicin (TRPV1 agonist, 1.6 μg/lip) or cinnamaldehyde (TRPA1 agonist, 13.2 μg/lip). In order to verify the involvement of TRPV1 and TRPA1 channels, others groups of mice were pretreated with the respective antagonist 15 min before administration of FTL. Nociception was quantified as time (s) spent rubbing the site of injection 0–5 min after induction. The interaction between FTL and TRPA1 was analyzed using molecular docking. The HEX software was used for molecular docking calculations and the direct action of FTL on TRPA1 was viewed using PyMOL v1.4.7. Experimental protocols were approved by the UNIFOR Animal Research Ethics Committee (#0122014). Pretreatment with FTL was associated with a reduction in the intensity of face rubbing induced by capsaicin (***p<0.001) or cinnamaldehyde (****p<0.0001). Ruthenium red, but not camphor, abolished the antinociceptive effect of FTL. It was possible to observe a direct action of FTL amino acids (Asp149, Tyr146, Trp 147 and Gly25) on TRPA1 glycosylated amino acids (1.8–3.6 Å). However, out of 10 more energetic clusters, only 4 overlapped, suggesting that there are repulsions and chemical impediments that hinder the FTL fitting more than once in the same site of the channel. The energies observed in the 10 investigated clusters are high, but do not exceed those previously observed for TRPV1 channel. FTL antinociceptive effect was abolished by the TRPV1 antagonist, but not by the TRPA1 antagonist and FTL. Besides this, FTL strongly interacts with TRPV1 and it has a weak interaction with TRPA1. Since and TRPV1 and TRPA1 channels are co‐expressed and they interact in neurons, we suggest that FTL effect is mediated by TRPV1.