Lateral hypothalamic area mediated the aggravated effect of microinjection of Baclofen into cerebellar fastigial nucleus on stress gastric mucosal damage in rats

Neuromechanism of acupuncture regulating gastrointestinal motility

Acupuncture has been used in China for thousands of years and has become more widely accepted by doctors and patients around the world. A large number of clinical studies and animal experiments have confirmed that acupuncture has a benign adjustment effect on gastrointestinal (GI) movement; however, the mechanism of this effect is unclear, especially in terms of neural mechanisms, and there are still many areas that require further exploration. This article reviews the recent data on the neural mechanism of acupuncture on GI movements. We summarize the neural mechanism of acupuncture on GI movement from four aspects: acupuncture signal transmission, the sympathetic and parasympathetic nervous system, the enteric nervous system, and the central nervous system.

The Roles of GABA in Ischemia-Reperfusion Injury in the Central Nervous System and Peripheral Organs

Ischemia-reperfusion (I/R) injury is a common pathological process, which may lead to dysfunctions and failures of multiple organs. A flawless medical way of endogenous therapeutic target can illuminate accurate clinical applications. γ-Aminobutyric acid (GABA) has been known as a marker in I/R injury of the central nervous system (mainly in the brain) for a long time, and it may play a vital role in the occurrence of I/R injury. It has been observed that throughout cerebral I/R, levels, syntheses, releases, metabolisms, receptors, and transmissions of GABA undergo complex pathological variations. Scientists have investigated the GABAergic enhancers for attenuating cerebral I/R injury; however, discussions on existing problems and mechanisms of available drugs were seldom carried out so far. Therefore, this review would summarize the process of pathological variations in the GABA system under cerebral I/R injury and will cover corresponding probable issues and mechanisms in using GABA-related drugs to illuminate the concern about clinical illness for accurately preventing cerebral I/R injury. In addition, the study will summarize the increasing GABA signals that can prevent I/R injuries occurring in peripheral organs, and the roles of GABA were also discussed correspondingly.

The Regulatory Effects of Lateral Hypothalamus Area GABAB Receptor on Gastric Ischemia-Reperfusion Injury in Rats

HIGHLIGHTS

The aim of the research was to determine the functional effects and molecular mechanisms of GABA_B receptor on ischemia reperfusion-induced gastric injury in rats.

The lateral hypothalamus area GABA_B receptor attenuated the ischemia reperfusion-induced gastric injury by up-regulating the production of GABA, GABA_BR, and down-regulating P-GABA_BR in the brain.

This work would provide a new therapeutic strategy for acute gastric injury.

Gastric ischemia-reperfusion (GI-R) injury progression is largely associated with excessive activation of the greater splanchnic nerve (GSN). This study aims to investigate the protective effects of GABA_B receptor (GABA_BR) in the lateral hypothalamic area (LHA) on GI-R injury. A model of GI-R injury was established by clamping the celiac artery for 30 min and then reperfusion for 1 h. The coordinate of FN and LHA was identified in Stereotaxic Coordinates and then the L-Glu was microinjected into FN, GABA_B receptor agonist baclofen, or GABA_B receptor antagonist CGP35348 was microinjected into the LHA, finally the GI-R model was prepared. The expression of GABA_BR, P-GABA_BR, NOX2, NOX4, and SOD in the LHA was detected by western blot, PCR, and RT-PCR. The expression of IL-1β, NOX2, and NXO4 in gastric mucosa was detected by western blot. We found that microinjection of L-Glu into the FN or GABA_B receptor agonist (baclofen) into the LHA attenuated GI-R injury. Pretreatment with GABA_B receptor antagonist CGP35348 reversed the protective effects of FN stimulation or baclofen into the LHA. Microinjection of baclofen into the LHA obviously reduced the expression of inflammatory factor IL-1β, NOX2, and NOX4 in the gastric mucosa.

Conclusion: The protective effects of microinjection of GABA_BR agonist into LHA on GI-R injury in rats could be mediated by up-regulating the production of GABA, GABA_BR, and down-regulating P-GABA_BR in the LHA.

Gut-Brain Axis in Gastric Mucosal Damage and Protection

Abstract: Background

The gut-brain axis plays a potential role in numerous physiological and pathological conditions. Several substances link stomach with central nervous system. In particular, hypothalamo-pituitary-adrenocortical axis, thyrotropin-releasing factor-containing nerve fibers and capsaicin-sensitive nerves are principal mediators of the harmful and protective central nervous system-mediated effects on gastric mucosa. Also, existing evidence indicates that nitric oxide, prostaglandins and calcitonin gene-related peptide play a role as final effectors of gastric protection.

Methods

We undertook a structured search of bibliographic databases for peer-reviewed research literature with the aim of focusing on the role of gut-brain axis in gastric damage and protection. In particular, we examined manuscripts dealing with the role of steroids, thyrotropin-releasing hormone, prostaglandins, melatonin, hydrogen sulfide and peptides influencing food intake (i.e. leptin, cholecystokinin, peptide YY, central glucagon–like peptide-1, and ghrelin). Also, the role of GABAergic and glutamatergic pathways in gastric mucosal protection have been examined.

Results

We found and reviewed 61 peer-reviewed papers dealing with the major aspects related to the role of gut brain axis in gastric mucosal damage and protection.

Conclusions

A dense neuronal network links stomach with central nervous system and a number of neurotransmitters and peptides functionally and anatomically related to central nervous system play a major role in contributing to gastric mucosal integrity.

Exploiting the mechanisms underlying the connection between brain and gut may lead to a better understanding of the pathophysiology of gastric mucosal injury and to an improvement in the prevention and, eventually, management of gastric damage.

Participation of NMDA receptors in the lateral hypothalamus in gastric erosion induced by cold-water restraint

The present study investigated whether neurons in the lateral hypothalamus (LH) play a role in the occurrence of gastric ulcerations induced by cold-water restraint. The first experiment indicated that bilateral N-methyl-d-aspartate (NMDA) lesions of the LH (20μg/1μl per side) reduced the amount of gastric ulceration induced by cold-water restraint. In the second experiment, the NMDA antagonist DL-2-amino-5-phosphonovaleric acid (APV; 2.5μg/0.5μl per side) or its vehicle was microinjected bilaterally into the LH prior to the cold-water restraint procedure. APV did not induce gastric ulcerations but reduced the amount of ulceration induced by cold-water restraint. These results indicate that NMDA receptors in the LH play an important role in the occurrence of gastric ulceration induced by cold-water restraint. The participation of the LH and possible neuronal circuitry involved in stress-induced ulceration are discussed.

GABA(A) receptor overexpression in the lateral hypothalamic area attenuates gastric ischemia‑reperfusion injury in rats

Excessive activation of the greater splanchnic nerve (GSN) has previously been determined to contribute to the progression of gastric ischemia‑reperfusion (GI‑R) injury. The present study was designed to estimate the protective effects of GABAA receptor (GABA(A)R) overexpression in the lateral hypothalamic area (LHA) against GI‑R injury. The GI‑R injury model was induced in rats by clamping the celiac artery for 30 min and then reperfusing for 1 h. Microinjection of recombinant adenoviral vectors overexpressing GABA(A)R (Ad‑GABA(A)R) or control adenoviral vectors (Ad‑Con) into the LHA was conducted in GI‑R and normal control rats. Significant protective effects were observed on day 2 after Ad‑GABA(A)R treatment in the GI‑R injury rats. Ad‑GABA(A)R treatment reduced plasma norepinephrine levels, plasma angiotensin II levels and peripheral GSN activity, but increased the gastric mucosal blood flow, as compared with Ad‑Con treatment. These results indicate that adenoviral vector‑induced GABA(A)R overexpression in the LHA blunts GSN activity and subsequently alleviates the effects of gastric injury in GI‑R rats.

γ-Aminobutyric acid-mediated neurotransmission in cerebellar-hypothalamic circuit attenuates gastric mucosal injury induced by ischemia-reperfusion

BACKGROUND

Excessive greater splanchnic nerve (GSN) activation contributes to the progression of gastric ischemia-reperfusion (GI-R) injury. This study was designed to investigate the protective mechanism of cerebellar fastigial nucleus (FN) stimulation against GI-R injury.

METHODS

The GI-R injury model was induced in rats by clamping the celiac artery for 30 min, and then reperfusion for 30 min, 1, 3, 6, or 24 h, respectively.

KEY RESULTS

Microinjection of L-Glu (3, 6, 12 μg) into the FN dose-dependently attenuated GI-R injury and GSN activity. In addition, there was an enhancement of gastric mucosal blood flow in GI-R rats. Pretreatment with the glutamic acid decarboxylase antagonist into the FN, the GABAA receptor antagonist into the lateral hypothalamic area or lesion of superior cerebellar peduncle all reversed the protective effects of the FN stimulation. Furthermore, the FN stimulation reduced the TUNEL-positive gastric mucosal cell and Bax-positive gastric mucosal cell in GI-R rats.

CONCLUSIONS & INFERENCES

These results indicate that the protective effects of the FN stimulation against GI-R injury may be mediated by attenuation of the excessive GSN activation, gastric mucosal cell apoptosis, and Bax expression in GI-R rats.