Activation of orexin system facilitates anesthesia emergence and pain control.

Orexin (also known as hypocretin) neurons in the hypothalamus play an essential role in sleep-wake control, feeding, reward, and energy homeostasis. The likelihood of anesthesia and sleep sharing common pathways notwithstanding, it is important to understand the processes underlying emergence from anesthesia. In this study, we investigated the role of the orexin system in anesthesia emergence, by specifically activating orexin neurons utilizing the designer receptors exclusively activated by designer drugs (DREADD) chemogenetic approach. With injection of adeno-associated virus into the orexin-Cre transgenic mouse brain, we expressed the DREADD receptor hM3Dq specifically in orexin neurons and applied the hM3Dq ligand clozapine to activate orexin neurons. We monitored orexin neuronal activities by c-Fos staining and whole-cell patch-clamp recording and examined the consequence of orexin neuronal activation via EEG recording. Our results revealed that the orexin-DREADD mice with activated orexin neurons emerged from anesthesia with significantly shorter latency than the control mice. As an indication of reduced pain sensitivity, these orexin-DREADD mice took longer to respond to the 55 °C thermal stimuli in the hot plate test and exhibited significantly less frequent licking of the formalin-injected paw in the formalin test. Our study suggests that approaches to activate the orexin system can be beneficial in postoperative recovery.

Little Black Boxes: Noncardiac Implantable Electronic Medical Devices and Their Anesthetic and Surgical Implications.

Implanted electronic medical devices. or stimulators such as pacemakers and nerve stimulators have grown enormously in diversity and complexity over recent decades. The function and potential interaction of these devices with the perioperative environment is of increasing concern for anesthesiologists and surgeons. Because of the innate electromagnetic environment of the hospital (operating room, gastrointestinal procedure suite, and imaging suite), implanted device malfunction, reprogramming, or destruction may occur and cause physical harm (including nerve injury, blindness, deafness, burn, stroke, paralysis, or coma) to the patient. It is critical for the anesthesiologist and surgeon to be aware of the function and interaction of implanted devices, both with other implanted devices and procedures (such as magnetic resonance imaging and cardioversion) in the hospital environment. Because of these interactions, it is imperative that proper device function is assessed when the surgical procedure is complete. This review article will discuss these important issues for 12 different types of "little black boxes," or noncardiac implantable electronic medical devices.