Neuroscience
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Mechanical allodynia impinges on the life quality of patients. Hen Egg Lysozyme (HEL) is a substance extracted from eggs that is commonly used to inhibit bacterial activity. The role of HEL in regulating and treating pain is unclear. ⋯ In addition, pre-given of HEL also significantly attenuates the static mechanical allodynia induced by overexpression of TACAN in mice, and the effect of HEL can be blocked by Parkin-siRNA. This indicates that HEL increases the expression of Parkin through epigenetic mechanisms and then decreases TACAN membrane trafficking in sensory neurons to relieve static mechanical hypersensitivity. Therefore, we reveal a novel function of HEL, which is a potential substance for the treatment of static mechanical pain.
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5-HT2A receptors (5-HT2ARs) are widely expressed in the central nervous system, including in the ventrolateral orbital cortex (VLO). The VLO is an important cortical component for pain processing. Brain 5-HT2ARs are implicated in both pro- and anti- nociceptive functions. ⋯ We found that knockdown of 5-HT2ARs in the VLO aggravated spontaneous pain and mechanical allodynia in mice after IoN-CCI. At the synaptic level, decreasing 5-HT2AR expression by shRNA or inhibition of 5-HT2AR activity by its antagonist ketanserin decreased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) of the neurons in the VLO, whereas 5-HT2AR partial agonist 2,5-Dimethoxy-4-iodoamphetamine (DOI) enhanced sEPSCs of the neurons in the VLO. In summary, 5-HT2ARs in the VLO modulate the trigeminal pain by regulating neuronal glutamatergic activity.
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Social communication of affective states between individuals, as well as actual experiences, influences their internal states and behaviors. Although prior stress experiences promote empathy-like behaviors, it remains unclear whether the social transmission of stress events modulates these behaviors. Here, we provide evidence that transferred stress experiences from cage mates modulate socioaffective approach-avoidance behaviors in rats. ⋯ The next day, the subjects were allowed to explore two unfamiliar conspecifics; one was a naïve, while the other was a distressed conspecific that received two foot-shocks (1.0 mA, 5 s) immediately before the test. Rats that were housed with stressed mates, as well as those that experienced a higher intensity of foot-shocks, were more likely to approach, while naïve rats avoided, a distressed conspecific. These results suggest that socially transferred stress shifts socioaffective response styles from avoidance to approach toward a stressed conspecific in rats.