A single methamphetamine administration rapidly decreases vesicular dopamine uptake.
Recent studies demonstrated that vesicular dopamine (DA) uptake can be rapidly altered in synaptic vesicles purified from the striata of stimulant-treated rats. Specifically, a single administration of the plasmalemmal DA transporter inhibitor, cocaine, or the DA D(2) agonist, quinpirole, increases vesicular DA uptake in vesicles purified from the striata of treated rats. These effects of cocaine are prevented by pretreatment with a D(2), but not D(1), DA receptor antagonist. The purpose of the present study was to characterize the effect of a mechanistically different psychostimulant, methamphetamine (METH), on vesicular DA uptake. Results demonstrated that a single administration of this DA-releasing agent rapidly and reversibly decreased vesicular DA uptake. The METH-related decrease in vesicular DA uptake was attenuated by pretreatment with the D(2) antagonist, eticlopride, but not the D(1) antagonist, SCH23390 (R-[+]-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine). Core body temperature did not contribute to the effects of METH on vesicular DA uptake. Neither quinpirole nor cocaine increased vesicular DA uptake when rats were concurrently treated with METH. These studies provide further evidence that psychostimulants rapidly and differentially modify vesicular DA uptake. In addition, these studies demonstrate a complex role for D(2) DA receptors in altering vesicular DA transport.
Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Salt Lake City, UT 84112, USA.
Jeffrey M
JM
Brown
Evan L
EL
Riddle
Verónica
V
Sandoval
Raul K
RK
Weston
Jarom E
JE
Hanson
Michael J
MJ
Crosby
Yvette V
YV
Ugarte
James W
JW
Gibb
Glen R
GR
Hanson
Annette E
AE
Fleckenstein
D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D050483:Dopamine Plasma Membrane Transport Proteins; D007700:Kinetics; D008297:Male; D008562:Membrane Glycoproteins; D049990:Membrane Transport Modulators; D026901:Membrane Transport Proteins / Q000037:antagonists & inhibitors*; D008694:Methamphetamine / Q000494:pharmacology*; D009419:Nerve Tissue Proteins; D019257:Quinpirole / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D049990:Membrane Transport Modulators; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D019257:Quinpirole; D008694:Methamphetamine; D004298:Dopamine