Role of cannabinoids in the treatment of Tinnitus

Tinnitus is a frequent symptom in audiological clinical practice characterized by an abnormal noise perceived in one or both ears or in the head, in which a patient has a conscious hearing percept in absence of external sound. Tinnitus might be caused by a homeostatic response of central dorsal cochlear nucleus auditory neurons that makes them hyperactive in compensation to auditory input loss. One hypothesis suggests that tinnitus is a sensory form of epilepsy that involves the cochlear nucleus and the inferior colliculus, which display impairment in the electrical activity in the auditory system. This alteration determines a synaptic plasticity in the dorsal cochlear nucleus that becomes a target for pharmacological compounds able to treat tinnitus. There is no effective drug treatment for tinnitus, but different studies propose the use of cannabinoid receptors agonist for their anti-epileptic activity, although their practical effects are still unclear. In this review, we want to analyze the emerging pharmacological approaches of cannabinoid receptor agonists to the therapy of tinnitus.