Octopamine drives honeybee thermogenesis

In times of environmental change species have two options to survive: they either relocate to a new habitat or they adapt to the altered environment. Adaptation requires physiological plasticity and provides a selection benefit. In this regard, the Western honeybee (Apis mellifera) protrudes with its thermoregulatory capabilities, which enables a nearly worldwide distribution. Especially in the cold, shivering thermogenesis enables foraging as well as proper brood development and thus survival. In this study, we present octopamine signaling as a neurochemical prerequisite for honeybee thermogenesis: we were able to induce hypothermia by depleting octopamine in the flight muscles. Additionally, we could restore the ability to increase body temperature by administering octopamine. Thus we conclude, that octopamine is necessary and sufficient for thermogenesis. Moreover, we show that these effects are mediated by β octopamine receptors. The significance of our results is highlighted by the fact the respective receptor genes underlie enormous selective pressure due to adaptation to cold climates. Finally, octopamine signaling in the service of thermogenesis might be a key strategy to survive in a changing environment.

Accidental perioperative hypothermia

The problem of perioperative hypothermia is still relevant. There are many reasons for that. One of them: a decrease in the patient’s body temperature during the operation often goes unnoticed, or is not perceived by medical staff as a serious complication. Perioperative unintentional hypothermia is a decrease in the patient’s core body temperature <36 °C in the periods: 1 h before anesthesia, during surgery and 24 h after anesthesia. Usually a decrease in body temperature activates the hypothalamic mechanisms of thermoregulation, which provide first vasoconstriction, which reduces heat loss, and then the development of cold shivering (contractile thermogenesis) – heat production. Modern anesthetics affect the regulation of central temperature and lead to its reduction in the perioperative period. Unintentional intraoperative hypothermia accompanies many surgeries performed under general and regional anesthesia. It is perhaps the most important factor in the “triad of death” (hypovolemia, acidosis, hypothermia), which significantly increases the risk of complications, including: prolongation of the duration of action of anesthetics and muscle relaxants and the recovery period; increase in the volume of intraoperative blood loss; from the cardiovascular system complications up to fatal consequences; development of wound infection, increase in wound healing time; increasing the frequency of cold shivering, nausea and vomiting in the postoperative period. Thus, perioperative hypothermia leads to an increase in hospitalization and nosocomial mortality. An important role in the prevention and relief of perioperative hypothermia is played by the competence and motivation of the nurse to timely and effective action in all areas of the perioperative process using thermometry methods available in a specific medical institution (axillary, esophageal or tympanic), prevention of heat loss through the skin under the influence of the environment (room air temperature, operating and equipment), passive and active (convection systems) heating patients with a body temperature <36 °C, rapid thawing and heating to 37 °C of allogeneic blood components. It is especially important during emergency operations, when it is necessary to start warming and temperature monitoring in the intensive care unit of the admission department.