Brown Slime Cap Mushroom (Chroogomphus rutilus, Agaricomycetes) Polysaccharide Resists Motion Sickness by Inhibiting the Activity of the Serotonin System in Mice.

Motion sickness (MS) is a disorder of the autonomic nervous system caused by abnormal exercise with symptoms such as nausea, vomiting and drowsiness. More than 90% of the human population has experienced different degrees of MS. At present, anticholinergics, antihistamines, and sympathomimetic drugs are used for treating MS, but these drugs generally have some adverse reactions and are not suitable for all people. Therefore, it is necessary to develop anti-MS drugs that have high efficiency and no adverse effects. Previous studies have found that Chroogomphus rutilus polysaccharide (CRP) is effective at preventing and treating MS in rats and mice. However, its mechanism of action is not clear. To clarify whether the CRP has anti-MS effects in mice, and to clarify its mechanism, we performed behavioral, biochemical, and morphological tests in a Kunming mouse model. Our results indicate that CRPs can significantly relieve the symptoms of MS, and their effect is equivalent to that of scopolamine, a commonly used anti-MS medicine. Our results indicate that CRPs may directly act on the gastrointestinal chromaffin cells to inhibit the synthesis and release of serotonin (5-hydroxytryptamine, or 5-HT) and thus reduce the signal from the gastrointestinal tract.

Modulatory effects of somatosensory electrical stimulation on neural activity of the dorsal cochlear nucleus of hamsters.

The effects of somatosensory electrical stimulation on the dorsal cochlear nucleus (DCN) activity of control and tone-exposed hamsters were investigated. One to three weeks after sound exposure and control treatment, multiunit activity was recorded at the surface of the left DCN before, during, and after electrical stimulation of the basal part of the left pinna. The results demonstrated that sound exposure induced hyperactivity in the DCN. In response to electrical stimulation, neural activity in the DCN of both control and exposed animals manifested four response types: S-S, suppression occurring during and after stimulation; E-S, excitation occurring during stimulation and suppression after; S-E, suppression occurring during stimulation and excitation after; and E-E, excitation occurring during and after stimulation. The results showed that there was a higher incidence of suppressive (up to 70%) than of excitatory responses during and after stimulation in both groups. In addition, there was a significantly higher degree of suppression after, rather than during stimulation. At high levels of electrical current, the degree of the induced suppression was generally higher during and after stimulation in exposed animals than in controls. The similarity of our results to those of previous clinical studies further supports the view that DCN hyperactivity is a direct neural correlate of tinnitus and that somatosensory electrical stimulation can be used to modulate DCN hyperactivity. Optimization of stimulation strategy through activating only certain neural pathways and applying appropriate stimulation parameters may allow somatosensory electrical stimulation to be used as an effective tool for tinnitus suppression.