[Molecular stress response in the stomach]

Sex Specific Alterations in α4*Nicotinic Receptor Expression in the Nucleus Accumbens

Background: The mechanisms leading from traumatic stress to social, emotional and cognitive impairment and the development of mental illnesses are still undetermined and consequently there remains a critical need to develop therapies for preventing the adverse consequences of traumatic stress. Research indicates nicotinic acetylcholine receptors containing α4 subunits (α4*nAChRs) are both impacted by stress and capable of modulating the stress response. In this study, we investigated whether varenicline, a partial α4β2*nAChR agonist which reduces nicotine, alcohol and sucrose consumption, can reduce stress, a driving factor in substance use disorders. We also examined the effect of stress on nucleus accumbens (NAc) α4*nAChR expression. Methods: Transgenic mice with fluorescent tags attached to α4*nAChRs were administered varenicline and/or yohimbine (a pharmacological stressor) and plasma corticosterone and NAc α4*nAChR expression were measured. A separated group of mice were exposed to maternal separation (MS) during post-natal day (P) 2–14, then restraint stressed (30 min) at six weeks of age. Body weight, anxiety-like behaviours (elevated plus maze), plasma corticosterone and NAc α4*nAChR levels were measured. Results: Varenicline attenuated yohimbine-induced plasma corticosterone increases with no effect on NAc α4*nAChR expression. MS reduced unrestrained plasma corticosterone levels in both sexes. In females, MS increased body weight and NAc α4*nAChR expression, whereas, in males, MS and restraint caused a greater change in anxiety-like behaviours and plasma corticosterone levels. Restraint altered NAc α4*nAChR expression in both male and female MS mice. Conclusions: The effects of stress on NAc α4*nAChR are sex-dependent. While varenicline attenuated acute stress-induced rises in corticosterone levels, future studies are required to determine whether varenicline is effective for relieving the effects of stress.

Expression of protein disulfide isomerase in gastric mucosa infected with Helicobacter pylori

AIM: To study the expression of protein disulfide isomerase (PDI) in gastric mucosa infected with H. pylori.

METHODS: Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to examine the mRNA and protein expression of PDI, respectively, in human gastric mucosa with or without H. pylori infection (n = 32 or 28).

RESULTS: The expression amounts of PDI mRNA and protein were 0.5704 ± 0.0794 and 0.5198 ± 0.0379 in the mucosa without H. pylori infection, which were significantly lower than those in the ones with H. pylori infection (1.0642 ± 0.1533, 0.8252 ± 0.0321, P < 0.01).

CONCLUSION: H. pylori infection can increase the transcription of PDI mRNA and synthesis of PDI protein in gastric mucosa.

Expression of glucose-regulation protein 94 in gastric mucosa infected with Helicobacter pylori

AIM

To study the expression of glucose regulation protein 94 in gastric mucosa infected with Helicobacter pylori.

METHODS

Semi-quantitative RT-PCR method was used to demonstrate mRNA expression of Grp94 in H.pylori (Hp) infected and non-infected gastric mucosa. Western blot was used to detect the expression level of Grp94 protein in the tissues.

RESULTS

Hp negative group had 28 cases, and the expression amount of Grp94 mRNA was 0.424±0.055. Hp infected group had 32 cases and the expression amount of Grp94 mRNA was 0.882±0.082. The expression amounts of Grp94 protein were 0.427±0.036, 0.671±0.072 respectively in Hp-negative and positive groups. The expression amounts of Grp94 mRNA and Grp94 protein in infected group showed a significant increase (P<0.01) respectively.

CONCLUSION

H.pylori infection may increase the expression of Grp94 at mRNA level in gastric mucosa. Meanwhile, it also increases synthesis of the protein.