Serotonergic function in cocaine addicts: prolactin responses to sequential D,L-fenfluramine challenges

Area of Science:

• Neuroscience
• Psychiatry
• Pharmacology

Background:

• Cocaine abuse is known to affect serotonergic function, but human studies are limited.
• Understanding these alterations is crucial for developing effective treatments for cocaine addiction.

Purpose of the Study:

• To assess central serotonergic responsivity in cocaine addicts versus controls.
• To investigate the impact of cocaine discontinuation on serotonergic function.
• To examine the influence of a paternal history of substance abuse on these responses.

Main Methods:

• Neuroendocrine challenges using D,L-fenfluramine (FEN), a serotonin releaser and reuptake inhibitor.
• Measurement of plasma prolactin levels in 25 male cocaine addicts and 13 healthy male controls.
• Repeated challenges during cocaine abstinence (weeks 1 and 3) and subgroup analysis based on family history (FH+ vs. FH-).

Main Results:

• Increased prolactin response to FEN over time during cocaine abstinence in the patient group.
• Significantly blunted early prolactin responses in FH+ patients compared to FH- patients and controls.
• More pronounced rebound in FH+ patients' responses, normalizing late-stage comparisons.

Conclusions:

• Cocaine use significantly impacts human serotonergic mechanisms involved in prolactin release.
• Individuals with a paternal history of substance abuse exhibit heightened vulnerability to cocaine's disruptive effects on serotonin function.
• The observed blunted and rebound prolactin responses suggest a potential indicator of increased susceptibility to addiction.