Evidence for tinnitus-related plasticity in the auditory and limbic system, demonstrated by arg3.1 and c-fos immunocytochemistry

• Published in: Hearing research 2004-09, Vol.195 (1), p.17-34
• Main Authors: Mahlke, C., Wallhäusser-Franke, E.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Amygdala; Amygdala - drug effects; Amygdala - physiopathology; Animals; arg3.1/arc; Auditory cortex; Auditory Cortex - drug effects; Auditory Cortex - physiopathology; Auditory Pathways - drug effects; Auditory Pathways - metabolism; Biological and medical sciences; Cell Count; Cochlear Nucleus - drug effects; Cochlear Nucleus - metabolism; Cytoskeletal Proteins - metabolism; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Female; Fundamental and applied biological sciences. Psychology; Gerbillinae; Immunohistochemistry; Inferior Colliculi - drug effects; Inferior Colliculi - metabolism; Injections; Male; Medical sciences; Nerve Tissue Proteins - metabolism; Neuronal Plasticity; Neurons - metabolism; Neurons - pathology; Non tumoral diseases; Otorhinolaryngology. Stomatology; Proto-Oncogene Proteins c-fos - metabolism; Salicylate; Salicylates - administration & dosage; Salicylates - pharmacology; Sodium Chloride - administration & dosage; Sodium Chloride - pharmacology; Tinnitus; Tinnitus - chemically induced; Tinnitus - metabolism; Tinnitus - pathology; Tinnitus - physiopathology; Vertebrates: nervous system and sense organs
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/j.heares.2004.03.005

Distributions of arg3.1 and c-fos immunoreactive neurons (IRN) in gerbil auditory cortex (AC) and amygdala showed characteristic differences when comparing systemic application of the tinnitus-eliciting drug salicylate with acoustic stimulation or saline injections. In AC, arg3.1 IRN induced by stimulation focused in regions corresponding to the frequency content of the stimulus. Injections of salicylate (350 mg/kg body weight) led to accumulation of arg3.1 IRN in the high frequency domain, while saline injections produced a diffuse distribution. After all treatments, c-fos IRN outnumbered arg3.1 IRN in AC and showed a broad distribution. In subcortical auditory structures arg3.1 IRN were absent in all but one brain. In ventral cochlear nucleus, c-fos IRN were always found after stimulation and often also after saline injections, whereas none were present when injecting salicylate. Similarly, in inferior colliculus, numbers of c-fos IRN were lowest after salicylate injections. In the amygdala, c-fos and arg3.1 IRN were increased substantially after salicylate injections compared to auditory stimulation or saline injections. In particular in its central nucleus, c-fos and arg3.1 IRN were found exclusively after the tinnitus-inducing treatment, suggesting that coactivation of the AC and the amygdala may by an essential feature of tinnitus-related activation.