Distribution and colocalization of melatonin 1a-receptor and NADPH-d in the trigeminal system of rat

Expression of nitric oxide synthases in rat odontoblasts and the role of nitric oxide in odontoblastic differentiation of rat dental papilla cells

As precursor cells of odontoblasts, dental papilla cells (DPCs) form the dentin-pulp complex during tooth development. Nitric oxide (NO) regulates the functions of multiple cells and organ tissues, including stem cell differentiation and bone formation. In this paper, we explored the involvement of NO in odontoblastic differentiation. We verified the expression of NO synthase (NOS) in rat odontoblasts by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining and immunohistochemistry in vivo. The expression of all three NOS isoforms in rat DPCs was confirmed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), immunofluorescence, and western blotting in vitro. The expression of neuronal NOS and endothelial NOS was upregulated during the odontoblastic differentiation of DPCs. Inhibition of NOS function by NOS inhibitor l-N^G -monomethyl arginine (L-NMMA) resulted in reduced formation of mineralized nodules and expression of dentin sialophosphoprotein (DSPP) and dentin matrix protein (DMP1) during DPC differentiation. The NO donor S-nitroso-N-acetylpenicillamine (SNAP, 0.1, 1, 10, and 100 μM) promoted the viability of DPCs. Extracellular matrix mineralization and odontogenic markers expression were elevated by SNAP at low concentrations (0.1, 1, and 10 μM) and suppressed at high concentration (100 μM). Blocking the generation of cyclic guanosine monophosphate (cGMP) with 1H-(1,2,4)oxadiazolo-(4,3-a)quinoxalin-1-one (ODQ) abolished the positive influence of SNAP on the odontoblastic differentiation of DPCs. These findings demonstrate that NO regulates the odontoblastic differentiation of DPCs, thereby influencing dentin formation and tooth development.

Safety and Efficacy of Melatonin in Chronic Tension-Type Headache: A Post-Marketing Real-World Surveillance Program

INTRODUCTION

Tension-type headache (TTH) is the most prevalent primary headache. Every year, about 2-3% of patients with TTH progress to chronic TTH with daily or near-daily headache, warranting preventive treatment. The treatment of chronic TTH is complex and very often associated with significant tolerability issues. To date, melatonin has been studied in only a few small uncontrolled trials. The aim of this surveillance program was to evaluate the efficacy of melatonin (Melaxen^®) in patients with TTH and disruption of circadian rhythms in real-world practice.

METHODS

Sixty-one patients with chronic TTH were enrolled. After the 30-day baseline period, patients took 3 mg of melatonin at bedtime for 30 days with a follow-up period of another 30 days. VAS pain intensity assessments, Hamilton Anxiety Rating Scale (HAM-A), Hamilton Depression Rating Scale (HAM-D), HIT-6 and Levin sleep quality scores were obtained at the baseline visit, at month 1, and month 2.

RESULTS

A significant decrease in the number of headache days per month, VAS pain intensity, HAM-A, HAM-D and HIT-6 scores, and an improvement in sleep quality were observed throughout the study. No treatment-emergent adverse events were reported.

CONCLUSIONS

Melatonin is an effective and safe alternative for the treatment of chronic TTH.