Papel del núcleo parabraquial lateral en los circuitos tanto nociceptivo como antinociceptivo de la rata

One of the most important advances for the comprehension and treatment of the pain has been the discovery of an endogenous circuit of modulation of the nociceptive information. Recently, has been involved to the lateral parabrachial nucleus (LPB) in the above mentioned circuit, though its role in the transmission and / or modulation of the pain is not sufficiently clear. LPB is strategically placed, from the anatomical point of view, to influence both the transmission and the control of the pain. In the present study, we decide to investigate the role that the LPB might play in the mechanism of transmission of painful different stimuli, as the somatic superficial one (test of the formalina) and the visceral one (test of the abdominal contractions), as well as, in the mechanism of action of different analgesic drugs, as the metamizol (500 mg/kg) and the morphine (10 mg/kg), using the immunocytochemical detection of the protein Fos as a marker of neuronal activity. We used male Sprague-Dawley rats as experimental animal. We can conclude from our results that: 1) LPB plays a role in the somatic nociceptive circuit, principally by the superior (slPB) and dorsal (dlPB) subnucli; 2) LPB plays a role in the visceral nociceptive circuit, principally by the external subnucleus (elPB); 3) LPB plays a role in the mechanism of action of the metamizol, principally by the external (elPB) and central (clPB) subnucli; 4) LPB does not play a role in the mechanism of action of the morphine, at least by the expression of the c-fos proto-oncogen.