[The action of L-DOPA on the spontaneous activity generated by the isolated spinal cord of 16- to 20-day-old chick embryos].
Effect of bath application of L-DOPA, dopamine (DA), noradrenaline (NA) on the spontaneous activity--cyclical oscillations of electrotonic potentials in dorsal and ventral roots (DR and VR, respectively) generated by isolated spinal cord of 16-20-day-old chick embryo was studied. L-DOPA in low concentration (30-150 mumol/l) activated spinal generator: suprathreshold rhythms appeared (i.e., spike activity in DR and VR). High concentration (200-1000 mumol/l) of L-DOPA depressed generator activity, but in the course of washing of the spinal cord spontaneous activity was enhanced and suprathreshold rhythms appeared. DA and NA (50 mumol/l) did not influence the activity but in concentration 100 mumol/l they depressed spontaneous activity in DR and VR. Bath application of 2-amino-5-phosphonovaleric acid (20 mumol/l) blocked activity induced by small concentration of L-DOPA. Activity generated by the neuronal network of the isolated dorsal horn was intensified after bath-application of L-DOPA in small concentration. Rhythmic activity in the isolated ventral horn did not appear after bath-application of L-DOPA. It is concluded that excitatory action of L-DOPA on the neuronal network of dorsal horn chick embryo was direct (i.e., did not depend on catecholamines).
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D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D002642:Chick Embryo; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007980:Levodopa / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D010507:Periodicity; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D013126:Spinal Nerve Roots / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D007980:Levodopa; D015763:2-Amino-5-phosphonovalerate; D004298:Dopamine; D009638:Norepinephrine
Deĭstvie L-DOFA na spontannuiu aktivnost', generiruemuiu izolirovannym spinnym mozgom 16--20-dnevnykh kurinykh émbrionov.