ISSN:
1435-1463
Keywords:
Keywords: Ventral tegmental area
;
excitatory amino acids
;
medial prefrontal cortex
;
non-DA neurons
;
synaptic plasticity
;
behavioural sensitisation.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary. Evidence suggests that sensitisation to the behavioural effects of d-amphetamine involves a late-onset (〉3 hrs), long-term potentiation (LTP)-like change at medial prefrontal cortex (mPFC)-regulated synapses on A10 dopaminergic (DA) neurons. Since muscimol-induced excitation of A10 DA neurons is dependent on mPFC-regulated afferents, this assay was used to assess whether d-amphetamine enhances the driving of A10 DA neurons by the mPFC, as would be predicted if it resulted in the conditions necessary for LTP. Animals were administered d-amphetamine or saline, 3–4.5 hrs prior to recording. In the acute condition, animals were drug-naïve prior to d-amphetamine, whilst in the challenge condition, animals had previously received d-amphetamine (or saline) each day for 6 days. Recording took place on withdrawal day 2. Muscimol produced significantly less inhibition of A10 DA neurons from animals administered d-amphetamine (rather than saline), but only when d-amphetamine had been chronically administered beforehand (i.e. in the challenge condition). Hence, although the studies fail to provide evidence that acute d-amphetamine administration produces the conditions necessary for LTP, chronic d-amphetamine administration appears to potentiate the impact on A10 DA neurons of mPFC-regulated excitatory activity, thus strengthening the link between this potentiation and the sensitisation process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007020070002
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