Local salsolinol modulates dopamine extracellular levels from rat nucleus accumbens: shell/core differences

Salsolinol (SAL), a condensation product of dopamine and acetaldehyde that appears in the rat and human brain after ethanol ingestion, has been largely implicated in the aetiology of alcoholism. Although the behavioural consequences of systemic or intracerebral SAL administrations have been described, the neurochemical effects of pharmacologically relevant doses of SAL and other tetrahydroisoquinolines (THIQs) in the brain areas involved in alcohol addiction are practically unknown. To gain an insight into this topic, male Wistar rats were stereotaxically implanted with one concentric microdialysis probe in either the shell or the core of the nucleus accumbens (NAc). Treatments involved local administration of 0.1, 5 and 25 microM SAL for 20 min through the dialysis probe. Dopamine (DA) concentrations in the shell or core of the NAc were on-line analyzed every 20 min by HPLC with electrochemical detection. Implantation of the probe was histologically evaluated at the end of the experiments. Our results indicate that dialysis application of 5 and 25 microM SAL into the core increased the dialysate levels of DA. Conversely, the administration of the same doses of this drug into the shell significantly reduced the DA levels in this subregion. In conclusion, these data reveal that local application of SAL affects the DA levels in the NAc subterritories in a region-specific manner. These findings may prove useful in probing CNS sites and mechanisms involved in alcohol consumption.