Biology subjects

Mohamad Ibrahim, K.

Publications and source records attributed to Mohamad Ibrahim, K..

2 recordsLinked to original sources

bioRxiv2025

Preoptic activation induces a torpor-like hypothermic and hypometabolic state that is cerebroprotective

Therapeutic hypothermia for stroke has been limited by shivering, increased metabolic demand, and poor patient tolerance. Engaging endogenous thermoregulatory circuits to lower body temperature may overcome these limitations and modulate metabolism, offering an integrated approach to cerebroprotection. Here, we show that chemogenetic activation of neurons in the preoptic area (POA) elicits a torpor-like state in mice, characterized by sustained hypothermia and hypometabolism. In an animal stroke model, this endogenous hypothermic state significantly reduced infarct volume and improved motor outcomes compared to controls, whereas maintaining normothermia attenuated these protective effects. To explore metabolic mechanisms contributing to this state, we performed untargeted metabolomic profiling 30 minutes after POA activation and identified coordinated shifts in nucleotide, phospholipid, and sphingolipid pathways. These rapid, temperature-dependent changes indicate a metabolically reprogrammed state that may enhance neuronal resilience during ischemic stress. Together, our findings suggest that POA-driven hypothermia confers cerebroprotection through specific metabolic adaptations with translational potential.

neuroscience↗

bioRxiv2024

Inflammatory pain in mice induces light cycle-dependent effects on sleep architecture

As a syndrome, chronic pain comprises physical, emotional, and cognitive symptoms such as disability, negative affect, feelings of stress, and fatigue. A rodent model of long-term inflammatory pain, induced by complete Freunds adjuvant (CFA) injection, has previously been shown to cause anhedonia and dysregulated naturalistic behaviors, in a manner similar to animal models of stress. We examined whether this extended to alterations in circadian rhythms and sleep, such as those induced by chronic social defeat stress, using actigraphy and wireless EEG. CFA-induced inflammatory pain profoundly altered sleep architecture in male and female mice. Injection of the hind paw, whether with CFA or saline, reduced some measures of circadian rhythmicity such as variance, period, and amplitude. CFA increased sleep duration primarily in the dark phase, while sleep bout length was decreased in the light and increased in the dark phase. Additionally, CFA reduced wake bout length, especially during the dark phase. Increases in REM and SWS duration and bouts were most significant in the dark phase, regardless of whether CFA had been injected at its onset or 12 hours prior. Taken together, these results indicate that inflammatory pain acutely promotes but also fragments sleep.

neuroscience↗