The neuronal nicotinic acetylcholine receptors alpha 4* and alpha 6* differentially modulate dopamine release in mouse striatal slices.
Striatal dopamine (DA) plays a major role in the regulation of motor coordination and in the processing of salient information. We used voltammetry to monitor DA-release evoked by electrical stimulation in striatal slices, where interneurons continuously release acetylcholine. Use of the alpha6-selective antagonist alpha-conotoxin MII[E11A] and alpha4 knockout mice enabled identification of two populations of DA-ergic fibers. The first population had a low action potential threshold, and action potential-evoked DA-release from these fibers was modulated by alpha6. The second population had a higher action potential threshold, and only alpha4(non-alpha6) modulated action potential-evoked DA-release. Striatal DA-ergic neurons fire in both tonic and phasic patterns. When stimuli were applied in a train to mimic phasic firing, more DA-release was observed in alpha4 knockout versus wild-type mice. Furthermore, block of alpha4(non-alpha6), but not of alpha6, increased DA release evoked by a train. These results indicate that there are different classes of striatal DA-ergic fibers that express different subtypes of nicotinic receptors.
Meyer
Erin L
EL
Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.
Yoshikami
Doju
D
McIntosh
J Michael
JM
D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000235:genetics / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011978:Receptors, Nicotinic / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*
D004298:Dopamine; D011978:Receptors, Nicotinic; C104518:nicotinic receptor alpha6