PKA is required in the induction and early-phase maintenance of LTP of C-fiber evoked field potentials in spinal dorsal horn of adult rats / 中国病理生理杂志

ABSTRACT

AIM: The role of cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) in the induction and maintenance of spinal long-term potentiation (LTP) was evaluated. METHODS: The C-fiber evoked field potentials were recorded at the superficial layers of spinal dorsal horn at the lumbar enlargement. RESULTS: (1) 8-Br-cAMP induced LTP of C-fiber evoked field potentials and 8-Br-cAMP-induced LTP occludes tetanus-induced LTP. (2) Rp-CPT-cAMPS, an inhibitor of PKA, blocked the induction of spinal LTP and reversed established LTP of C-fiber evoked field potentials in a time-dependent manner. (3) In the presence of anisomycin, a protein synthesis inhibitor, the potentiation induced by 8-Br-cAMP was completely blocked. (4) PD98059, a selective inhibitor of mitogen-activated protein kinase (MAPK),completely blocked the 8-Br-cAMP-induced LTP.CONCLUSION: Activation of PKA signal pathway in spinal dorsal horn may be crucial for the induction and the early-phase maintenance of LTP of C-fiber evoked field potentials.