[Semax potentiates effects of D-amphetamine on the level of extracellular dopamine in the Sprague-Dawley rat striatum and on the locomotor activity of C57BL/6 mice].
The synthetic peptide semax (a fragment of ACTH 4-7 Pro-Gly-Pro) enhances the release of extracell dopamine (DA) induced by D-amphetamine (5 mg/kg) in the striatum of Spraig-Dowley (SD) rats and increases the locomotor activity stimulated by D-amphetamine (2 mg/kg) in C57/BL6 mice. The basal content of DA, 3,4-dihydroxyphenylacetic acid (DHPAA), and homovanillic acid (HVA) in dialysate of SD rats was 0.5-1.0, 996 +/- 25, and 761 +/- 37 pmole/ml, respectively (n = 7). D-amphetamine (5 mg/kg) induced a sharp increases in the DA level (up to 20 pmole/ml) 20-40 min after treatment and reduced the extracell DHPAA content to 30% of the basal level for a prolonged time (over the entire experimental period). Preliminary (20 min before D-amphetamine) administration of semax resulted in a greater peak of DA concentration (p < 0.05) and a more pronounced drop in DHPAA level (p < 0.01) as compared to the effects produced by the psychostimulant alone. In behavioral tests on C57/BL6 mice, D-amphetamine (2 mg/kg) increased the locomotor activity to a level of 182% (p < 0.01). Simultaneous introduction of semax (0.6 mg/kg) and D-amphetamine (2 mg/kg) led to a more pronounced increase in the locomotor activity of mice (261%, p < 0.01). It is suggested that the peptide modulates dopaminergic systems involved in the formation of the psychostimulant effect.
Eremin
K O
KO
Zakusov Institute of Pharmacology, Russian Academy of Medical Sciences, Baltiiskaya ul. 8, Moscow, 125315 Russia.
Saransaari
P
P
Oja
S
S
Raevskiĭ
K S
KS
D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D004357:Drug Synergism; D045604:Extracellular Fluid / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects*; D018697:Nootropic Agents / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D015259:Dopamine Agents; D018697:Nootropic Agents; D010446:Peptide Fragments; C048487:ACTH (4-7), Pro-Gly-Pro-; D000324:Adrenocorticotropic Hormone; D003913:Dextroamphetamine; D004298:Dopamine