Neurochemical features of endomorphin-2-containing neurons in the submucosal plexus of the rat colon

Development of a novel three-dimensional injection guide for trigeminal ganglia

BACKGROUND

Trigeminal ganglion (TG) plays an important role in the process of orthodontic pain. It's necessary to design an accurate, precise and minimally invasive trigeminal ganglion injection guide plate to study TG.

METHODS

Micro-CT was used to obtain the Dicom format data, and three-dimensional (3D) software (mimics and magics23.03) was used to reconstruct 3D head models. Design and modifications of the TG injection guide plate were performed in Magic 23.03 software, and the guide plate was produced by a 3D stereolithography printer. X-ray, micro-CT, Evans blue, and virus transduction were used to demonstrate the accuracy of the guide-assisted injection. Pain levels were evaluated after using the injection guide by a bite force test and Von Frey test.

RESULTS

X-ray and micro-CT tests confirmed that the injection needle reached the bilateral trigeminal ganglia fossa. The Evans blue test and virus transduction proved that the injected drug could be accurately injected into the bilateral trigeminal ganglion and the lentivirus could be successfully transfected. The percentage of accurate injection was 10/10 (bilateral trigeminal ganglia). Orofacial pain induced by the trigeminal ganglion injection was mild and returned to baseline within seven days.

CONCLUSION

The injection guide described in this study is viable and reliable for the delivery of drugs and virus transduction into the trigeminal ganglia.

Mycotoxins and the Enteric Nervous System

Mycotoxins are secondary metabolites produced by various fungal species. They are commonly found in a wide range of agricultural products. Mycotoxins contained in food enter living organisms and may have harmful effects on many internal organs and systems. The gastrointestinal tract, which first comes into contact with mycotoxins present in food, is particularly vulnerable to the harmful effects of these toxins. One of the lesser-known aspects of the impact of mycotoxins on the gastrointestinal tract is the influence of these substances on gastrointestinal innervation. Therefore, the present study is the first review of current knowledge concerning the influence of mycotoxins on the enteric nervous system, which plays an important role, not only in almost all regulatory processes within the gastrointestinal tract, but also in adaptive and protective reactions in response to pathological and toxic factors in food.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Opioidergic effects on enteric and sensory nerves in the lower GI tract: basic mechanisms and clinical implications

Opioids are one of the most prescribed drug classes for treating acute pain. However, chronic use is often associated with tolerance as well as debilitating side effects, including nausea and dependence, which are mediated by the central nervous system, as well as constipation emerging from effects on the enteric nervous system. These gastrointestinal (GI) side effects limit the usefulness of opioids in treating pain in many patients. Understanding the mechanism(s) of action of opioids on the nervous system that shows clinical benefit as well as those that have unwanted effects is critical for the improvement of opioid drugs. The opioidergic system comprises three classical receptors (μ, δ, κ) and a nonclassical receptor (nociceptin), and each of these receptors is expressed to varying extents by the enteric and intestinal extrinsic sensory afferent nerves. The purpose of this review is to discuss the role that the opioidergic system has on enteric and extrinsic afferent nerves in the lower GI tract in health and diseases of the lower GI tract, particularly inflammatory bowel disease and irritable bowel syndrome, and the implications of opioid treatment on clinical outcomes. Consideration is also given to emerging developments in our understanding of the immune system as a novel source of endogenous opioids and the mechanisms underlying opioid tolerance, including the potential influence of opioid receptor splice variants and heteromeric complexes.