Sex-dependent role of Neuropeptide-S on anxiety, fear conditioning, and alcohol seeking in alcohol preferring rats.

Alcohol Use Disorder (AUD) is a global health concern, with stress playing a crucial role in its development and persistence. Currently, no pharmacotherapies specifically targeting stress are approved for AUD treatment. Neuropeptide S (NPS) plays a dual role in stress regulation, exhibiting both anxiolytic and stress-enhancing effects. While NPS reduces alcohol self-administration (ASA) in alcohol preferring rats, its role in AUD-related stress and anxiety remains unclear. This study investigated the behavioral effects of NPS in male and female Marchigian Sardinian alcohol-preferring (msP) rats. To assess its impact on locomotion, anxiety, and fear memory, we conducted an open-field, an elevated plus maze (EPM), and a fear conditioning (FC) paradigm following intracerebroventricular administration of NPS. Furthermore, we examined the effects of NPS on ASA and yohimbine-induced reinstatement of alcohol-seeking in msP rats. Our results indicate that NPS administration increased locomotor activity in both sexes and selectively alleviated generalized anxiety levels in male rats in the EPM test. In the FC task, administration of NPS immediately after FC test facilitated the extinction of fear memories in females but not in males. Notably, NPS reduced ASA in both female and male rats but did not alter yohimbine-induced reinstatement of alcohol-seeking. In conclusion, NPS modulates anxiety in a sex-dependent manner. Since both alcohol and NPS alleviate anxiety and fear conditioning in msP rats, NPS may reduce alcohol intake by replacing the anxiolytic properties of alcohol. These effects appear to be sex-dependent, with NPS primarily alleviating generalized anxiety in males and facilitating fear extinction in females.