The lateral habenula nucleus regulates pruritic sensation and emotion.

Itch is a complex aversive sensory and emotional experience. As a most upsetting symptom in many dermatological and systemic diseases, it lacks efficient treatments. The lateral habenula nucleus (LHb) encodes negative emotions in the epithalamus and has been implicated in pain and analgesia. Nevertheless, the role of the lateral habenula nucleus in the pruritic sensation and emotion remains elusive. Here we defined the crucial role of glutamatergic neurons within the lateral habenula nucleus (GluLHb) in itch modulation in mice. We established histamine-dependent and histamine-independent models of acute pruritus, as well as the acetone-ether-water (AEW) model of chronic pruritus. We first assessed the effects of pruritogen injection on neural activation in both medial and lateral divisions of LHb in vitro. We then demonstrated that the population activity of GluLHb neurons was increased during the acute itch and chronic itch-induced scratching behaviors in vivo. In addition, electrophysiological data showed that the excitability of GluLHb neurons was enhanced by chronic itch. Chemogenetic suppression of GluLHb neurons disrupted both acute and chronic itch-evoked scratching behaviors. Furthermore, itch-induced conditioned place aversion (CPA) was abolished by GluLHb neuronal inhibition. Finally, we dissected the LHb upstream brain regions. Together, these findings reveal the involvement of LHb in processing both the sensational and emotional components of pruritus and may shed new insights into itch therapy.

[A comparative study of sentinel lymph node detection in laryngeal and hypopharyngeal carcinoma by lymphoscintigraphy method and blue dye].

OBJECTIVE: To investigate the clinical value of sentinel lymph node (SLN) detection in laryngeal and hypopharyngeal carcinoma patients with clinically negative neck (cN0) by lymphoscintigraphy method and blue dye. METHODS: Forty patients with cN0 laryngeal neoplasms and ten patients with cN0 hypopharyngeal carcinoma scheduled for tumor resection and neck dissection, were eligible for the study. single photon emission computed tomography (SPECT)/CT lymphoscintigraphy was performed with injection of radioactivity isotope 99Tc(m) labeled sulfur colloid (99Tc(m)-SC). Methylthioninium was injected into the same points as 99Tc(m)-SC during surgery, and the patients underwent lymphatic mapping with a handheld gamma-detecting probe. All removed lymph nodes were examined by routine histopathology. RESULTS: Thirty-five patients with laryngeal carcinoma and six patients with hypopharyngeal carcinoma detected SLN by radiolabeled tracer method, the detection rate of SLN was 82.0%. Twenty-nine patients with laryngeal carcinoma and 4 patients with hypopharyngeal carcinoma detected SLN by blue dye method, the detection rate of SLN was 66.0%. There were significant difference between two groups (chi² = 2.769, P < 0.05), and the number of SLN were respectively 96 and 83 by radiolabeled tracer method and blue dye (chi² = -2.098, P < 0.05), The sensitivity of SLN detection were respectively 83.3% and 66.7%. Twelve (24.0%) patients had lymph node metastasis. CONCLUSIONS: Either lymphoscintigraphy or blue dye mapping can be used to detect the SLN in cN0 laryngeal and hypopharyngeal carcinoma. The lymphoscintigraphy not only preoperatively can locate the accuracy of SLN detection, but also has higher detection rate and sensitivity than dye method.