Selective serotonin reuptake inhibitors increase sympathetic activity under heavy alcohol exposure in rat models

Diminazene aceturate attenuates systemic inflammation via microbiota gut-5-HT brain-spleen sympathetic axis in male mice

The sympathetic arm of the inflammatory reflex is the efferent pathway through which the central nervous system (CNS) can control peripheral immune responses. Diminazene aceturate (DIZE) is an antiparasitic drug that has been reported to exert protective effects on various experimental models of inflammation. However, the pathways by which DIZE promotes a protective immunomodulatory effects still need to be well established, and no studies demonstrate the capacity of DIZE to modulate a neural reflex to control inflammation. C57BL/6 male mice received intraperitoneal administration of DIZE (2 mg/Kg) followed by lipopolysaccharide (LPS, 5 mg/Kg, i.p.). Endotoxemic animals showed hyperresponsiveness to inflammatory signals, while those treated with DIZE promoted the activation of the inflammatory reflex to attenuate the inflammatory response during endotoxemia. The unilateral cervical vagotomy did not affect the anti-inflammatory effect of DIZE in the spleen and serum. At the same time, splenic denervation attenuated tumor necrosis factor (TNF) synthesis in the spleen and serum. Using broad-spectrum antibiotics for two weeks showed that LPS modulated the microbiota to induce a pro-inflammatory profile in the intestine and reduced the serum concentration of tryptophan and serotonin (5-HT), while DIZE restored serum tryptophan and increased the hypothalamic 5-HT levels. Furthermore, the treatment with 4-Chloro-DL-phenylalanine (pcpa, an inhibitor of 5-HT synthesis) abolished the anti-inflammatory effects of the DIZE in the spleen. Our results indicate that DIZE promotes microbiota modulation to increase central 5-HT levels and activates the efferent sympathetic arm of the inflammatory reflex to control splenic TNF production in endotoxemic mice.

Caspofungin Effects on Electrocardiogram of Mice: An Evaluation of Cardiac Safety

Caspofungin is an echinocandin, exhibiting efficacy against most Candida species invasive infection. Its cardiotoxicity was reported in isolated rat heart and ventricular myocytes, but in vivo and clinical studies are insufficient. Our objective was to evaluate caspofungin in vivo cardiac effects using an efficacious dose against Candida albicans. Female Swiss mice were infected with C. albicans, and treated with caspofungin, 5 or 10 mg/kg, intraperitoneal along 5 days. Survival rate and colony-forming units (CFU) into vital organs were determined. For cardiac effects study, mice were treated with caspofungin 10 mg/kg, and electrocardiogram (ECG) signal was obtained on C. albicans-infected mice, single dose-treated, and uninfected mice treated along 5 days, both groups to measure ECG intervals. Besides, ECG was also obtained by telemetry on uninfected mice to evaluate heart rate variability (HRV) parameters. The MIC for caspofungin on the wild-type C. albicans SC5314 strain was 0.3 μg/ml, indicating the susceptible. Survival rate increased significantly in infected mice treated with caspofungin compared to mice treated with vehicle. None of the survived infected mice presented positive CFU after treatment with 10 mg/kg. C. albicans infection induced prolongation of QRS, QT, and QTc intervals; caspofungin did not alter this effect. Caspofungin induced increase of PR and an additional increase of QRS after 24 h of a single dose in infected mice. No significant alterations occurred in ECG intervals and HRV parameters of uninfected mice, after caspofungin treatment. Caspofungin showed in vivo cardiac relative safety maintaining its antifungal efficacy against C. albicans.

Assessment of Skin Blood Flow Following Acute Intravenous Alcohol, and Association with Subjective Perceptions, in Social Drinkers

BACKGROUND

The objective of this study was to determine the effect of acute intravenous (IV) alcohol infusion on skin blood flow (SBF) response, measured at fingertip and earlobe, and subjective responses associated with SBF in social drinkers.

METHODS

Twenty-four social drinkers underwent a computer-assisted alcohol self-infusion study. SBF was measured continuously using laser Doppler flow meter, with the probe placed on the fingertip or earlobe. Perfusion recordings were collected at baseline, and at 0-minute (0 to 5 minutes), 10-minute (10 to 15 minutes), and 20-minute (20 to 25 minutes) time points during the priming phase of IV alcohol self-administration paradigm at low breath alcohol levels of approximately 30 mg%. Subjective response was measured using the Drug Effects Questionnaire (DEQ) and Biphasic Alcohol Effects Scale.

RESULTS

Overall SBF (collective data from both fingertip and earlobe) and SBF by each site showed significant drop at 0 minutes and then subsequent significant elevation with alcohol self-administration. Males showed higher overall SBF at baseline and 0 minutes than the females. At fingertip site, lowering in 0-minute SBF compared to baseline, and subsequent significant increase at the 10- and 20-minute SBF recordings were observed. DEQ measures of "like" and "want more" alcohol were significantly associated with 10- and 20-minute SBF recordings collected at fingertip site.

CONCLUSIONS

The changes in SBF following acute IV alcohol exposure are consistent with the sympathetic response of alcohol on the cardiovascular system. This acute hemodynamic effect characterizes differences in blood flow that are sensitive to relatively low levels of acute alcohol exposure. The association of subjective perceptions with the SBF response provides evidence of the psychophysiological effects of alcohol at low levels of exposure.