Hm. Arnold et al., Systemic and intra-accumbens administration of amphetamine differentially affects cortical acetylcholine release, NEUROSCIENC, 96(4), 2000, pp. 675-685
The present experiments tested the hypothesis that the amphetamine-induced
increase in dopamine release in the nucleus accumbens represents a necessar
y and sufficient component of the ability of systemically administered amph
etamine to stimulate cortical acetylcholine release. The effects of systemi
c or intra-accumbens administration of amphetamine on accumbens dopamine re
lease and cortical acetylcholine release were assessed simultaneously in aw
ake animals equipped with dialysis probes inserted into the shell of the nu
cleus accumbens and the medial prefrontal cortex. Additionally, the ability
of intra-accumbens administration of dopamine D-1 and D-2 receptor antagon
ists to attenuate the effects of systemic amphetamine on cortical acetylcho
line was tested. The effects of all treatments were assessed in interaction
with a stimulus-induced activation of cortical acetylcholine release to ac
count for the possibility that the demonstration of the trans-synaptic effe
cts of accumbens dopamine requires pre-activation of basal forebrain circui
ts. Systemic amphetamine resulted in increases in basal cortical acetylchol
ine and accumbens dopamine efflux. Intra-accumbens administration of amphet
amine substantially increased accumbens dopamine efflux, but did not signif
icantly affect cortical acetylcholine efflux. Furthermore, intra-accumbens
administration of sulpiride or SCH 23390 did not attenuate the systemic amp
hetamine-induced increase in cortical acetylcholine efflux.
Collectively, the present data suggest that increases in accumbens dopamine
release are neither sufficient nor necessary for the effects of systemical
ly administered amphetamine on cortical acetylcholine release. The systemic
amphetamine-induced increase in cortical acetylcholine may be mediated via
multiple, parallel pathways and may not be attributable to a single affere
nt pathway of the basal forebrain. (C) 2000 IBRO. Published by Elsevier Sci
ence Ltd.