Tropisetron But Not Granisetron Ameliorates Spatial Memory Impairment Induced by Chronic Cerebral Hypoperfusion

Effect of preoperative tropisetron treatment on postoperative cognitive function: A retrospective cohort study

To investigate the effect of preoperative tropisetron treatment on postoperative cognitive function on the basis of patients' Mini-Cog scale scores. In this retrospective cohort study, data were retrieved from the medical record database. This research did not involve concerns with patient safety and violation of their interests, and therefore, no ethical review was required. Depending on tropisetron exposure status, patients were assigned to the exposure group (86 patients) and the non-exposure group (74 patients). Patients in the exposure and non-exposure groups were administered tropisetron (10 mg; intravenously 15 minutes before operation) and other antiemetics, respectively. Data on the patients' demographic characteristics, American society of Anesthesiologists (ASA) classification, comorbid underlying diseases, sleep quality, education level, anesthesia method, duration of fasting, intraoperative blood loss and fluid replacement, intraoperative minimum and maximum systolic blood pressures (SBPs), intraoperative minimum and maximum diastolic blood pressures (DBPs), postoperative Mini-Cog scale (a simple intelligence status assessment scale) score, and postoperative visual analogue scale (VAS) pain score were collected in both the groups. The postoperative Mini-Cog score (as an indicator of cognitive function) and the rate of postoperative cognitive impairment were compared between the exposure and non-exposure groups. A multifactorial logistic regression equation was constructed to analyze the factors associated with impaired cognitive function in the postoperative period. The postoperative cognitive impairment rate in the exposure group was significantly lower than that in the non-exposure group (3.5% vs 16.2%; P < .05). Multifactorial logistic regression analysis suggested that tropisetron was a protective factor for postoperative cognitive function, with a statistically significant effect (odds ratio [OR] = 5.04, 95% confidence interval [CI] = 1.31-19.4). Preoperative tropisetron exposure significantly reduces the incidence of postoperative cognitive impairment in patients, and it is a protective factor for postoperative cognitive function.

Cognitive Impairments and blood-brain Barrier Damage in a Mouse Model of Chronic Cerebral Hypoperfusion

Chronic cerebral hypoperfusion (CCH) is commonly involved in various brain diseases. Tight junction proteins (TJs) are key components constituting the anatomical substrate of the blood-brain barrier (BBB). Changes in cognitive function and BBB after CCH and their relationship need further exploration. To investigate the effect of CCH on cognition and BBB, we developed a bilateral common carotid artery stenosis (BCAS) model in Tie2-GFP mice. Mice manifested cognitive impairments accompanied with increased microglia after the BCAS operation. BCAS mice also exhibited increased BBB permeability at all time points set from D1 to D42. Furthermore, BCAS mice showed reduced expression of TJs 42 d after the operation. In addition, correct entrances of mice in radial arm maze test had a moderate negative correlation with EB extravasation. Our data suggested that BCAS could lead to cognitive deficits, microglia increase and BBB dysfunction characterized by increased BBB permeability and reduced TJs expression level. BBB permeability may be involved in the cognitive impairments induced by CCH.

Xi-Xian-Tong-Shuan capsule alleviates vascular cognitive impairment in chronic cerebral hypoperfusion rats by promoting white matter repair, reducing neuronal loss, and inhibiting the expression of pro-inflammatory factors

BACKGROUND

While the number of cases of vascular cognitive impairment caused by chronic cerebral hypoperfusion (CCH) has been increasing every year, there are currently no clinically effective treatment methods. At present, Xi-Xian-Tong-Shuan capsule is predominantly used in patients with acute cerebral ischemia; however, its protective effect on CCH has rarely been reported.

OBJECTIVE

To explore the underlying mechanisms by which Xi-Xian-Tong-Shuan capsule alleviates cognitive impairment caused by CCH.

METHODS

A model of CCH was established in specific-pathogen-free (SPF)-grade male Sprague-Dawley (SD) rats using bilateral common carotid artery occlusion (BCCAO). Xi-Xian-Tong-Shuan capsules were intragastrically administered for 42 days after the BCCAO surgery. We then assessed for changes in cognitive function, expression levels of pro-inflammatory factors, and coagulation function as well as for the presence of white matter lesions and neuronal loss. One-way ANOVA and Tukey's test were used to analyze the experimental data.

RESULTS

The rats showed significant cognitive dysfunction after the BCCAO surgery along with white matter lesions, a loss of neurons, and elevated levels of inflammatory factors, all of which were significantly reversed after intervention with Xi-Xian-Tong-Shuan capsules.

CONCLUSION

Xi-Xian-Tong-Shuan capsules can ameliorate vascular cognitive impairment in CCH rats by preventing damage of white matter, reducing neuronal loss, and inhibiting the expression of pro-inflammatory factors. Our study provides a new reference for the clinical treatment of chronic cerebral ischemia with Xi-Xian-Tong-Shuan capsules.

Modulating role of serotonergic signaling in sleep and memory

Serotonin is an important neurotransmitter with various receptors and wide-range effects on physiological processes and cognitive functions including sleep, learning, and memory. In this review study, we aimed to discuss the role of serotonergic receptors in modulating sleep-wake cycle, and learning and memory function. Furthermore, we mentioned to sleep deprivation, its effects on memory function, and the potential interaction with serotonin. Although there are thousands of research articles focusing on the relationship between sleep and serotonin; however, the pattern of serotonergic function in sleep deprivation is inconsistent and it seems that serotonin has not a certain role in the effects of sleep deprivation on memory function. Also, we found that the injection type of serotonergic agents (systemic or local), the doses of these drugs (dose-dependent effects), and up- or down-regulation of serotonergic receptors during training with various memory tasks are important issues that can be involved in the effects of serotonergic signaling on sleep-wake cycle, memory function, and sleep deprivation-induced memory impairments. This comprehensive review was conducted in the PubMed, Scopus, and ScienceDirect databases in June and July 2021, by searching keywords sleep, sleep deprivation, memory, and serotonin.