Anesthetic Agents: Neurotoxics or Neuroprotectives?

Annually, millions of surgeries are carried out worldwide under general anesthesia. Patients undergoing elective or emergency procedures may have important comorbidities affecting significant functions such as cardiovascular, neurologic, and metabolic. Physicochemical and pharmacological properties differ between anesthetic drugs. Different molecular reactions within the human body are triggered by surgery and anesthesia. Cellular protective mechanisms against any kind of insult may be either enhanced or attenuated under general anesthesia. An extensive literature supporting neurotoxic effects of anesthetic drugs has been published in animal models including nonhuman primates, whereas human data are limited. Surgery and anesthesia exposure may be related to a higher incidence of neurological dysfunction mostly in extreme age patients (children and older patients). Postoperative cognitive dysfunction, delirium, and progression of previously diagnosed neurodegenerative disorders are some of the unsatisfactory clinical outcomes. Apoptosis has been described as a common mechanism triggered by intracellular reactions after anesthesia exposure. Nevertheless, some anesthetics may inhibit these pathways limiting cellular injury. Some anesthetics are associated with a protective effect as a result of enzymatic modulation and activation of antiapoptotic proteins.