Orexin A and B in the rat superior salivatory nucleus

Neuropeptides regulate embryonic salivary gland branching through the FGF/FGFR pathway in aging klotho-deficient mice

Salivary gland branching morphogenesis is regulated by the functional integration of neuronal signaling, but the underlying mechanisms are not fully understood in aging accelerated klotho-deficient (Kl-/-) mice. Here, we investigated whether the neuropeptides substance P (SP) and neuropeptide Y (NPY) affect the branching morphogenesis of embryonic salivary glands in aging Kl-/- mice. In the salivary glands of embryonic Kl-/- mice, morphological analysis and immunostaining revealed that epithelial bud formation, neuronal cell proliferation/differentiation, and the expression of the salivary gland functional marker ZO-1 were decreased in embryonic ductal cells. Incubation with SP/NPY at E12-E13d promoted branching morphogenesis, parasympathetic innervation, and epithelial proliferation in salivary glands of embryonic Kl-/- mice. The ERK inhibitor U0126 specifically inhibited neuronal substance-induced epithelial bud formation in the embryonic salivary gland. RNA-seq profiling analysis revealed that the expression of fibroblast growth factors/fibroblast growth factors (FGFs/FGFRs) and their receptors was significantly regulated by SP/NPY treatment in the embryonic salivary gland (E15). The FGFR inhibitor BGJ389 inhibited new branching formation induced by SP and NPY treatment and ERK1/2 expression. These results showed that aging may affect virtually the development of salivary gland by neuronal dysfunction. The neuropeptides SP/NPY induced embryonic salivary gland development through FGF/FGFR/ERK1/2-mediated signaling.

Distribution of alpha-synuclein in rat salivary glands

Expression of alpha-synuclein (Syn), a presynaptic neuronal protein, was immunohistochemically examined in intact rat submandibular, sublingual, and lingual glands. The submandibular gland contained abundant periductal Syn-immunoreactive (-ir) nerve fibers. Abundant Syn-ir varicosities were present in acini of the sublingual and serous lingual glands. By confocal laser scanning microscopy, Syn-ir nerve fibers around smooth muscle actin (SMA)-ir cells alone were infrequent; however, those around aquaporin-5 (AQP5)-ir cells alone and both SMA- and AQP5-ir cells were abundant in the sublingual and serous lingual glands. SMA-ir cells were occasionally immunoreactive for toll-like receptor 4, a Syn receptor. Syn-ir nerve fibers contained tyrosine hydroxylase (TH) in the submandibular gland and choline acetyltransferase (ChAT) in all examined salivary glands. In the superior cervical (SCG), submandibular, and intralingual ganglia, sympathetic and parasympathetic neurons co-expressed Syn with TH and ChAT, respectively. SCG neurons innervating the submandibular gland contained mostly Syn. In the thoracic spinal cord, 14.7% of ChAT-ir preganglionic sympathetic neurons co-expressed Syn. In the superior salivatory nucleus, preganglionic parasympathetic neurons projecting to the lingual nerve co-expressed Syn and ChAT. The present findings indicate that released Syn acts on myoepithelial cells. Syn in pre- and post-ganglionic neurons may regulate neurotransmitter release and salivary volume and composition.

Pharmacological interventions for antipsychotic-related sialorrhea: a systematic review and network meta-analysis of randomized trials

Antipsychotic-induced sialorrhea carries a significant burden, but evidence-based treatment guidance is incomplete, warranting network meta-analysis (NMA) of pharmacological interventions for antipsychotic-related sialorrhea. PubMed Central/PsycInfo/Cochrane Central database/Clinicaltrials.gov/WHO-ICTRP and the Chinese Electronic Journal Database (Qikan.cqvip.com) were searched for published/unpublished RCTs of antipsychotic-induced sialorrhea (any definition) in adults, up to 06/12/2023. We assessed global/local inconsistencies, publication bias, risk of bias (RoB2), and confidence in the evidence, conducting subgroup/sensitivity analyses. Co-primary efficacy outcomes were changes in saliva production (standardized mean difference/SMD) and study-defined response (risk ratios/RRs). The acceptability outcome was all-cause discontinuation (RR). Primary nodes were molecules; the mechanism of action (MoA) was secondary. Thirty-four RCTs entered a systematic review, 33 NMA (n = 1958). All interventions were for clozapine-induced sialorrhea in subjects with mental disorders. Regarding individual agents and response, metoclopramide (RR = 3.11, 95% C.I. = 1.39-6.98), cyproheptadine, (RR = 2.76, 95% C.I. = 2.00-3.82), sulpiride (RR = 2.49, 95% C.I. = 1.65-3.77), propantheline (RR = 2.39, 95% C.I. = 1.97-2.90), diphenhydramine (RR = 2.32, 95% C.I. = 1.88-2.86), benzhexol (RR = 2.32, 95% C.I. = 1.59-3.38), doxepin (RR = 2.30, 95% C.I. = 1.85-2.88), amisulpride (RR = 2.23, 95% C.I. = 1.30-3.81), chlorpheniramine (RR = 2.20, 95% C.I. = 1.67-2.89), amitriptyline (RR = 2.09, 95% C.I. = 1.34-3.26), atropine, (RR = 2.03, 95% C.I. = 1.22-3.38), and astemizole, (RR = 1.70, 95% C.I. = 1.28-2.26) outperformed placebo, but not glycopyrrolate or ipratropium. Across secondary nodes (k = 28, n = 1821), antimuscarinics (RR = 2.26, 95% C.I. = 1.91-2.68), benzamides (RR = 2.23, 95% C.I. = 1.75-3.10), TCAs (RR = 2.23, 95% C.I. = 1.83-2.72), and antihistamines (RR = 2.18, 95% C.I. = 1.83-2.59) outperformed placebo. In head-to-head comparisons, astemizole and ipratropium were outperformed by several interventions. All secondary nodes, except benzamides, outperformed the placebo on the continuous efficacy outcome. For nocturnal sialorrhea, neither benzamides nor atropine outperformed the placebo. Active interventions did not differ significantly from placebo regarding constipation or sleepiness/drowsiness. Low-confidence findings prompt caution in the interpretation of the results. Considering primary nodes' co-primary efficacy outcomes and head-to-head comparisons, efficacy for sialorrhea is most consistent for the following agents, decreasing from metoclopramide through cyproheptadine, sulpiride, propantheline, diphenhydramine, benzhexol, doxepin, amisulpride, chlorpheniramine, to amitriptyline, and atropine (the latter not for nocturnal sialorrhea). Shared decision-making with the patient should guide treatment decisions regarding clozapine-related sialorrhea.

Distribution and possible function of galanin about headache and immune system in the rat dura mater

Galanin (GAL) is a nociceptive transmitter or modulator in the trigeminal sensory system. In this study, GAL expression was investigated in the rat dura mater to demonstrate its possible function in headache using immunohistochemical techniques. The cerebral falx and cerebellar dura mater received abundant blood and nerve supply, and were significantly thicker compared to other portions in the cerebral dura mater. GAL-immunoreactivity was expressed by cell and nerve fiber profiles. Presumed macrophages and dendritic cells contained GAL-immunoreactivity, and co-expressed with CD11b-immunoreactivity. Many isolated and perivascular nerve fibers also showed GAL-immunoreactivity. In addition, GAL-immunoreactive nerve fibers were present in the vicinity of macrophages and dendritic cells with either GAL- or ED1-immunoreactivity. GAL-immunoreactive cells and nerve fibers were common in the cerebral falx and cerebellar dura mater and infrequent in other portions. And, GAL-immunoreactive nerve fibers usually co-expressed calcitonin gene-related peptide (CGRP)-immunoreactivity. In the trigeminal ganglion, a substantial proportion of sensory neurons innervating the dura mater contained GAL-immunoreactivity (mean ± SD, 3.4 ± 2.2%), and co-expressed CGRP-immunoreactivity (2.7 ± 2.1%). The present study may suggest that GAL is associated with nociceptive transduction or modulation in the dura mater. GAL also possibly plays a role in the immune mechanism of the dura mater.