Nigrostriatal cell firing action on the dopamine transporter.
The influence of nigrostriatal cell firing on the dopamine transporter (DAT) activity of the rat striatum was studied in vivo with amperometric methods. Data were obtained after preventing dopamine (DA) release with alpha-methyl-L-tyrosine and replenishing extracellular DA with local injections. The DA cell stimulation, which under basal conditions increased extracellular DA, decreased DA after this pre-treatment, suggesting that firing activity facilitates the DA cell uptake of DA under these circumstances (drain response). Cocaine and GBR13069 markedly decreased the drain response, suggesting that it is dependent on DAT activation. Data obtained after haloperidol and apomorphine administration showed that the drain response was facilitated by pre-synaptic DA receptor stimulation but that receptors are not a necessary requirement. Two components in the drain response were observed, one with a short latency and duration that needed high-frequency stimuli, and the other with a long latency and duration that was even induced by low-frequency stimuli. This is the first evidence showing that DAT can be activated by the firing activity in nigrostriatal cells in a direct way and without the participation of pre-synaptic DA receptors.
Rodriguez
Manuel
M
Laboratory of Neurobiology and Experimental Neurology, Department of Physiology, Faculty of Medicine, University of La Laguna, La Laguna, 38320 Tenerife, Spain. mrdiaz@ull.es
Gonzalez
Sergio
S
Morales
Ingrid
I
Sabate
Magdalena
M
Gonzalez-Hernandez
Tomas
T
Gonzalez-Mora
Jose Luis
JL
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D004525:Efferent Pathways / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D018492:Dopamine Antagonists; D050483:Dopamine Plasma Membrane Transport Proteins; D008781:Methyltyrosines; C031476:alpha-methyl-m-tyrosine; D004298:Dopamine