Effects of octopamine on GABA-ergic transmission in rats.
The behavioral effects of octopamine (50, 100 and 250 micrograms/rat ivc) and GABA-ergic drugs alone or in combination were studied in rats. Octopamine significantly increased locomotor activity in all doses tested. In rats pretreated with muscimol (0.5 mg/kg sc) or baclofen (2.5 mg/kg ip) octopamine did not produce hyperactivity. Octopamine in all doses did not affect bicuculline (3.5 mg/kg sc) -induced convulsions. Picrotoxin (0.4 mg/kg sc) inhibited the stimulatory action of octopamine but at the same time produced signs of toxicity. Biochemical studies showed that octopamine decreased the cerebral concentration of GABA and reduced activity of GAD in rats brain. Significant changes in concentrations of NA and DA in brain of rats pretreated with baclofen and octopamine were found.
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D001921:Brain / Q000201:enzymology / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009118:Muscimol / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism; D009655:Octopamine / Q000494:pharmacology*; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000502:physiology*
D001418:Baclofen; D001640:Bicuculline; D004298:Dopamine; D005968:Glutamate Decarboxylase; D009118:Muscimol; D009638:Norepinephrine; D009655:Octopamine; D010852:Picrotoxin; D005680:gamma-Aminobutyric Acid