Mental nerve injury induces novelty seeking behaviour leading to increasing ethanol intake in Wistar rats.

OBJECTIVE: Dental treatment and orofacial surgeries may induce chronic neuropathic orofacial pain (CNOP). This kind of pain affects adaptability to environmental changes in both model animals and humans. Part of the adaptation process depends on the ability to distinguish between familiar and novel stimuli. CNOP induces novelty seeking behaviour as a deficit in environmental adaptation. Alternatively, novelty seeking is a sign for susceptibility to the development of substance abuse. Evidence shows that CNOP leads to alcoholism in animal models. The behavioural relationship between CNOP, novelty seeking behaviour and substance abuse is unknown. In this article, we investigate if CNOP produces an increase in novelty seeking and leads to increasing ethanol intake. DESIGN: Firstly, we used mental nerve injury as a neuropathic orofacial pain model to evaluate both thermal and mechanical allodynia. We used the novel recognition task to determine novelty seeking behaviour and the drink in darkness protocol to assess ethanol intake. RESULTS: Our results show that mental nerve constriction increases novelty seeking behaviour (p = 0.01) and correlates with ethanol binge consumption (r2 = 0.68, p = 0.0008). CONCLUSIONS: The present study demonstrates, for the first time, that trigeminal nerve injury, which induces CNOP, is enough to provide novelty seeking behaviour and lead to increasing ethanol intake. The increase of novelty seeking behaviour can serve as a predictor of risk of developing substance abuse. The treatment of CNOP involves a high risk of producing addiction. The level of novelty seeking evaluation in patients with neuropathic pain before treatment is critical.

Relationship between alcoholism addiction and periodontitis. an in vivo study using drinking-in-darkness protocol in rats

Periodontal disease (PD) has been considered a probable risk factor for several systemic diseases. among them, PD is presumed to be one of the possible etiologies of chronic illness of the central nervous system. In this context, poor oral health and PD is associated with substance abuse in humans. however, if periodontal lesions can produce addiction is unknown. this paper aims to evaluate the possibility that chronic periodontal injury (CPL) can cause ethanol binge intake in drink-in-darkness (DID) protocol in rats. in CPL group (n=10) experimental damage was done to the periodontal tissue of the second maxillary molar, the control group (n=9) received sham injury. forty-three days after CPL the intake of ethanol was assessed using several concentrations in DID experiment. during the DID experiment, we observed significant differences between the binge-type consumption of ethanol at the lowest concentration of 10 percent (p=0.01). differences in consumption of 20 percent ethanol are observed during a few days (p=0.04), and there are no differences in consumption at 40 percent concentration of ethanol (p=0.2). it is concluded that chronic periodontal lesion leads to alcoholism in wistar rats.