Effects of chronic nicotine on the temporal structure of anxiety-related behavior in rats tested in hole-board

• Published in: Progress in neuro-psychopharmacology & biological psychiatry 2020-01, Vol.96, p.109731, Article 109731
• Main Authors: Casarrubea, Maurizio, Pierucci, Massimo, Aiello, Stefania, Cassar, Daniel, Deidda, Gabriele, Crescimanno, Giuseppe, Di Giovanni, Giuseppe
• Format: Article
• Language: English
• Subjects: Animals; Anxiety; Anxiety - chemically induced; Anxiety - psychology; Chronic nicotine; Dose-Response Relationship, Drug; Drug Administration Schedule; Exploratory Behavior - drug effects; Exploratory Behavior - physiology; Hole-board; Male; Motor Activity - drug effects; Motor Activity - physiology; Nicotine - administration & dosage; Nicotine - toxicity; Random Allocation; Rats; Rats, Sprague-Dawley; Sprague-Dawley rats; T-pattern analysis; Time Factors
• ISSN: 0278-5846; 1878-4216
• DOI: 10.1016/j.pnpbp.2019.109731

The present study aimed to assess the behavioral effects of chronic treatments of different doses of nicotine by using both quantitative and multivariate T-pattern analysis (TPA), which can reveal hidden behavioral structures, in Sprague-Dawley rats tested in the hole-board apparatus. To this purpose, nicotine ditartrate was administered at the doses of 0.1, 0.5 and 1 mg/kg i.p., three times per day, for 14 consecutive days. As to quantitative evaluations, we observed significant reductions in the mean durations and mean frequencies of walking, climbing, immobile-sniffing and rearing in comparison to control. A significant reduction of edge-sniff and head-dip mean frequencies was also detected for all the doses tested. TPA revealed an increase in the number and the mean length of different T-patterns induced by the three doses of nicotine. On the other hand, a significant reduction of the mean occurrences of T-patterns was revealed. Overall, our results obtained by using both quantitative and T-pattern analyses indicate that chronic nicotine induces an anxiety condition characterized by a behavioral re-organization orbiting around the two main components of hole exploration, that is, head-dip and edge-sniff. A better understanding of the link between nicotine and anxiety might help to find new therapies for smoking cessation. •Chronic nicotine at 0.3, 1.5 and 3 mg/kg/day for 14 days induces anxiety-like behavior in rats tested in hole-board•Reduction of durations and occurrences of the exploratory components was detected in chronic nicotine-treated animals•Increase in the number and length of T-patterns was detected in chronic nicotine-treated animals