Comparison of the local anesthetic effects ON TOOTH PULP STIMULATION of A bufodienolide isolated from Bufoparacnemis venom with those of LIDOCAINE AND BUPIVACAINE

FREITAS, S.F., CARVALHO, I.F., CARDI, B.A., CARVALHO, M.D.F., CARVALHO, D.M.F., CARVALHO, K.M.

Laboratório de Neurofarmacologia, Universidade Estadual do Ceará, Fortaleza, CE, Brazil.

Objectives: The amphibian skin secretions contain several pharmacologically active compounds, such biogenic amines, toxins, peptides, enzymes and alkaloids, protecting then from predators and microorganisms. In this study, we compare the local anesthetic effects on tooth pulp stimulation of a bufodienolide isolated from Bufo paracnemis skin secretions with those of lidocaine and bupivacaine.

Methods and Results: The venom was dissolved in ethanol (1:3,w,v), centrifuged at 5000g/20 min and the supernatant was submitted to HPLC using a C₁₈ column (25x250mm)(5ml/min) eluted with acetonitrile(0-40%)(30min). The purified fraction (Bpa) with local anesthetic activity was pooled and lyophilized. High resolution NMR analysis of the purified factor by application of modern pulse sequences allowed its identification as a bufodienolide-type steroid, known in the literature as telecinobufagin. Local anesthetic activity was assayed with tooth pulp stimulation test in rabbit (n=6). Bpa, in the concentration of 0.5%, presented greater effect (p<0.05, 43±3.4Volts) than bupivacaine, in this same concentration (30±2.2Volts), and than lidocaine, in concentration of 2% (32±2.6Volts). Bpa, in the concentration of 0.5%, presented similar anesthetic time (160±12,5min) with that of bupivacaine, in this same concentration (150±11,9min), but longer than that of lidocaine, in concentration of 2% (50±4,5min).

Conclusions: a) Bpa(0.5%) presented greater local anesthetic effect than bupivacaine(0.5%) and than lidocaine (2%), b) Bpa (0.5%) presented similar anesthetic time with that of bupivacaine (0.5%) and longer than that of lidocaine (2%), c) although the mechanism of action of Bpa is unknown, it may be a tool to develop a new class of local anesthetics.

CORRESPONDENCE TO:

Krishnamurti de Morais Carvalho, Laboratório de Neurofarmacologia, Universidade Estadual do Ceará, Fortaleza, CE, Brazil. CEP: 60.000-000, Email: carvalhokris@hotmail.com