Cell type-specific effects of adenosine on cortical neurons.
Bottom Line: Although the effect of adenosine on subcortical areas has been previously described, the effects on cortical neurons have not been addressed systematically to date.We found that adenosine, via the A1 receptor, exerts differential effects depending on neuronal cell type and laminar location.These studies of the action of adenosine at the postsynaptic level may contribute to the understanding of the changes in cortical circuit functioning that take place between sleep and awakening.
Affiliation: Forschungszentrum Jülich, Institute of Neuroscience and Medicine, INM-2, D-52425 Jülich, Germany Current address: Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, 1105 BA Amsterdam, The Netherlands.Show MeSH
Related in: MedlinePlus
Mentions: To verify if adenosine acts mainly through the adenosine A1 receptor in the mPFC, we first made recordings from L5 pyramidal neurons and bath-applied adenosine and A1 specific agonists and antagonists. Bath application of 100 μM adenosine led on average to a 3.8 ± 0.3 mV hyperpolarization of the RMP of L5 pyramidal neurons (n = 30; Fig. 1A and Table 1). The size of the hyperpolarization was dependent on the adenosine concentration (Fig. 1B, EC50 18.6 ± 4.3 μM, n = 8), but bath application of 5 μM adenosine already caused a significant hyperpolarization [Fig. 1B, RMP: −66.1 ± 1.2 mV (control), −67.3 ± 1.2 mV (5 μM adenosine), difference −1.2 ± 0.4 mV, n = 10, paired t-test P < 0.01]. The effect of adenosine could be mimicked by bath application of 1 μM CPA, a specific agonist of the adenosine A1 receptor [Fig. 1C, RMP: −64.1 ± 1.3 mV (control), −67.9 ± 1.0 mV (CPA), difference −3.8 ± 0.6 mV, n = 4, paired t-test P < 0.01]. In addition, bath application of the adenosine A1 receptor antagonist CPT reversed the adenosine-induced hyperpolarization to baseline levels [Fig. 1D, RMP: −64.6 ± 3.0 mV (control), −66.6 ± 3.4 mV (adenosine), −64.7 ± 3.2 mV (adenosine + 1 μM CPT), n = 3, paired t-test P < 0.05].Table 1
Affiliation: Forschungszentrum Jülich, Institute of Neuroscience and Medicine, INM-2, D-52425 Jülich, Germany Current address: Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Science, 1105 BA Amsterdam, The Netherlands.