Biology subjects

Althoff, T.

Publications and source records attributed to Althoff, T..

3 recordsLinked to original sources

bioRxiv2026

Impact of opioid-based versus opioid-free anaesthesia on postoperative recovery, circulating inflammatory cytokines and brain-derived neurotrophic factor.

Background Opioid-free anaesthesia (OFA) has emerged as an alternative to opioid-based anaesthesia (OBA), but its benefit over OBA for postoperative quality of recovery (QoR) remains unclear. To address this question while limiting variability inherent in clinical studies, such as analgesic regimens and patient psychosocial factors, we investigated the effects of OFA versus OBA on postoperative recovery in a controlled preclinical mouse model. Methods Adult male and female C57BL/6J mice underwent laparotomy or sham procedures under isoflurane anaesthesia, and were randomly assigned to saline (control), fentanyl (OBA), or dexmedetomidine (OFA) as intraoperative analgesic adjuncts. All mice received multimodal postoperative analgesia, including carprofen. We adapted a standardised multidimensional recovery model using six behavioural endpoints reflecting human QoR domains: body weight, food intake, locomotor activity, mechanical sensitivity, sucrose preference, and social interaction. These endpoints were assessed on postoperative days 1, 2, 3, and 7. Plasma inflammatory cytokine and brain-derived neurotrophic factor (BDNF) concentrations were also measured in parallel as potential biological correlates of recovery. Results Over the study period, we observed no treatment effect across behavioural endpoints in laparotomised mice, including body weight (P=0.157), food intake (P=0.884), locomotor activity (P=0.864), mechanical sensitivity (P=0.628), sucrose preference (P=0.615), and social interaction (P=0.442). Composite QoR scores did not differ between OFA and OBA groups (P=0.569), with no differences in postoperative circulating inflammatory cytokine or BDNF concentrations. Conclusions Dexmedetomidine-based OFA and fentanyl-based OBA produced similar postoperative behavioural recovery, circulating inflammatory cytokine and BDNF trajectories in laparotomised mice receiving multimodal postoperative analgesia.

animal behavior and cognition↗

bioRxiv2026

A Wireless Wearable Platform for Intravenous Drug Self-Administration in Freely Behaving Rats

Studying how drugs act on neuronal circuits requires delivering them with temporal precision while behavior proceeds undisturbed, a combination that tethered infusion systems cannot provide. We developed WEARIT (Wireless Equipment for Autonomous Rat Infusion Tasks), a wearable, tetherless infusion platform that gives freely moving rats intravenous access under either remote or closed-loop operant control. The device houses a reservoir, miniaturized pump, rechargeable battery and Bluetooth circuitry in a 3D-printed enclosure worn on the back. By measuring spontaneous locomotion, amphetamine-induced hyperlocomotion and food-reinforced operant responding, we show that WEARIT leaves these behaviors unchanged. Remotely triggered fentanyl infusions yielded reliable delivery with physiological responses confirmed by pulse oximetry, and self-administration acquisition and dose-response functions were comparable to conventional tethered systems. WEARIT removes a longstanding constraint on intravenous pharmacology, opening self-administration paradigms to naturalistic and enriched environments and to concurrent imaging or optogenetic manipulation of the circuits engaged by drug reinforcement.

neuroscience↗

bioRxiv2019

The menstrual cycle is a primary contributor to cyclic variation in women’s mood, behavior, and vital signs

Female mood, behavior, and vital signs exhibit cycles which fundamentally affect health and happiness. However, it is unclear which dimensions of mood, behavior, and vital signs vary cyclically, how cycles at different timescales compare in magnitude, and how cycles vary across countries. Here we separate female mood, behavior, and vital signs into four simultaneous cycles - daily, weekly, seasonal, and menstrual. We analyze nine mood dimensions, three behavior dimensions, and three vital signs using a dataset of 241 million observations from 3.3 million women in 109 countries. We find that the menstrual cycle is a primary contributor to cyclic variation: it is the cycle with the largest amplitude for all three vital signs, sexual activity, and 7 out of 9 dimensions of mood. The amplitude of the menstrual happiness cycle is 1.4x the amplitude of the daily cycle, 3.3x the amplitude of the weekly cycle, 2.3x the amplitude of the seasonal cycle, and 1.7x the Christmas increase in happiness. Menstrual cycle effects are directionally consistent across countries, demonstrating that they occur across cultures. Overall, our results demonstrate the primacy of the menstrual cycle and necessitate better accounting for it in clinical data and practice.

physiology↗