ラット脊髄前角細胞におけるアデノシンによる神経保護作用について
詳細
To date, four subtypes of adenosine receptors, A1, A2A, A2B and A3 receptor, have been cloned and characterized.Although it has been reported that adenosine has neuroprotective effects, such as reducing the mortality of neurons and improving neurological deficits following brain injuries, it is still unknown whether adenosine has a neuroprotective action in the spinal cord. In the present study, we investigated cellular actions of adenosine in spinal ventral horn neurons by using whole-cell patch-clamp recordings in spinal slice preparations.Application of adenosine significantly decreased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in all ventral horn neurons recorded.An adenosine A1 selective agonist, CPA, also reduced sEPSC frequency in all ventral horn neurons recorded.In the presence of an adenosine A1 antagonist. DPCPX, adenosine or CPA did not decrease sEPSC frequency in all ventral horn neurons recorded.In addition, application of adenosine and CPA also produced outward currents in most of ventral horn neurons tested. In the presence of DPCPX, those outward currents were significantly suppressed. This study has provided a cellular basis for an involvement of pre- and postsynaptic adenosine A1 receptor in the neuroprotective actions of adenosine in the spinal ventral horn. Adenosine A1 receptor agonists may serve as a potential pharmacological tools to reduce loss of motor function in spinal cord injury patients. [J Physiol Sci. 2006;56 Suppl:S246]
