Presynaptic involvement of nitric oxide in dopamine D1/D5 receptor-induced sustained enhancement of synaptic currents mediated by ionotropic glutamate receptors in the rat hippocampus.
Using whole-cell patch-clamp recordings, the study tested the possibility whether nitric oxide (NO) was involved in dopamine D1/D5 receptor (D1/D5r)-induced sustained enhancement of excitatory postsynaptic currents (EPSCs) mediated by ionotropic glutamate receptors in rat hippocampal slices. Activation of D1/D5r by a selective agonist, 50 microM (+/-)-6-chloro-PB hydrobromide, elicited not only a sustained enhancement but also an increased frequency of spontaneous EPSC. The D1/D5r-induced effect was associated with decreases in paired-pulse facilitation (PPF). A selective inhibitor of neuronal NO synthase (nNOS), 100 microM 7-nitroindazole monosodium salt, substantially attenuated both the magnitudes of D1/D5r-induced enhancement and PPF decrease. These results suggest that presynaptic effects mediated by NO, possibly synthesized by nNOS, are involved in D1/D5-induced sustained enhancement of synaptic currents mediated by ionotropic glutamate receptors in the hippocampus.
Yang
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SN
Department of Physiology and Biophysics, National Defense Medical Center, Taipei, Taiwan, ROC. snyang@ndmc1.ndmctsgh.edu.tw
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000502:physiology*; D017447:Receptors, Dopamine D1 / Q000502:physiology; D050641:Receptors, Dopamine D5; D017470:Receptors, Glutamate / Q000502:physiology*; D013569:Synapses / Q000502:physiology*
D001552:Benzazepines; D018491:Dopamine Agonists; C493607:Drd5 protein, rat; D007191:Indazoles; D018696:Neuroprotective Agents; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017470:Receptors, Glutamate; D050641:Receptors, Dopamine D5; D009569:Nitric Oxide; C067113:SK&F 81297; C080122:7-nitroindazole