Experimental otoacoustic emission and auditory brainstem response changes by stellate ganglion blockage in rat

Sympathetic Nervous System Regulation of Auditory Function

BACKGROUND

The auditory system processes how we hear and understand sounds within the environment. It comprises both peripheral and central structures. Sympathetic nervous system projections are present throughout the auditory system. The function of sympathetic fibers in the cochlea has not been studied extensively due to the limited number of direct projections in the auditory system. Nevertheless, research on adrenergic and noradrenergic regulation of the cochlea and central auditory system is growing. With the rapid development of neuroscience, auditory central regulation is an extant topic of focus in research on hearing.

SUMMARY

As such, understanding sympathetic nervous system regulation of auditory function is a growing topic of interest. Herein, we review the distribution and putative physiological and pathological roles of sympathetic nervous system projections in hearing. Key Messages: In the peripheral auditory system, the sympathetic nervous system regulates cochlear blood flow, modulates cochlear efferent fibers, affects hair cells, and influences the habenula region. In central auditory pathways, norepinephrine is essential for plasticity in the auditory cortex and affects auditory cortex activity. In pathological states, the sympathetic nervous system is associated with many hearing disorders. The mechanisms and pathways of sympathetic nervous system modulation of auditory function is still valuable for us to research and discuss.

Effect of the stellate ganglion block on symptoms of ulcerative colitis: A case report

RATIONALE

Chronic ulcerative colitis is an autoimmune disease in which epithelial injury continuously occurs in the colonic mucosa. While mesalazine (5-aminosalicylic acid) is used to treat ulcerative colitis, it can also cause liver failure, headaches, and abdominal pain; therefore, an alternative treatment is required. The purpose of this study was to evaluate the effectiveness of 80 stellate ganglion blocks in reducing pain and other symptoms in a patient with chronic ulcerative colitis.

PATIENT CONCERNS

A 54-year-old female patient with a history of ulcerative colitis was concerned with worsening symptoms, such as abdominal discomfort and bloody-mucous stools, over the past 3 years.

DIAGNOSES

Oozing mucosal bleeding and a small amount of exudate were observed on colonoscopy; a diagnosis of ulcerative colitis was made upon histologic examination.

INTERVENTIONS AND OUTCOMES

A total of 80 stellate ganglion blocks were administered, after which the patient's symptom and pain level was decreased from 6 to 4 points on the numeric rating scale (11-point, 0 = no pain, 10 = worst pain imaginable). Improved clinical signs were observed on colonoscopy at a follow-up assessment.

LESSONS

The stellate ganglion block may be effective for the reduction of pain and other symptoms in patients with chronic ulcerative colitis.

Profile of minocycline neuroprotection in bilirubin-induced auditory system dysfunction

Excessive hyperbilirubinemia in human neonates can cause permanent dysfunction of the auditory system, as assessed with brainstem auditory evoked potentials (BAEPs). Jaundiced Gunn rat pups (jjs) exhibit similar BAEP abnormalities as hyperbilirubinemic neonates. Sulfadimethoxine (sulfa) administration to jjs, which displaces bilirubin from serum albumin into tissues including brain, exacerbates acute toxicity. Minocycline administered prior to sulfa in jjs protects against BAEP abnormalities. This study evaluates the neuroprotective capabilities of minocycline HCl (50 mg/kg) administered 30 or 120 min after sulfa (200 mg/kg) in 16 days old jjs. BAEPs are recorded at 6 or 24 h post-sulfa. Abnormal BAEP waves exhibit increased latency and decreased amplitude. The sulfa/saline treated jjs exhibited a significantly increased interwave interval between waves I and II (I-II IWI) and significantly decreased amplitudes of waves II and III compared to the saline/saline jjs. The minocycline 30 min post-sulfa (sulfa/mino+30) group was not significantly different from the saline/saline control group, indicating neuroprotection. The minocycline 120 min post-sulfa (sulfa/mino+120) group had a significantly decreased amplitude of wave III at both 6 and 24h. These studies indicate that minocycline has a graded neuroprotective effect when administered after acute bilirubin neurotoxicity.