Beta-adrenergic receptor function is acutely altered in surgical patients

Area of Science:

• Anesthesiology
• Pharmacology
• Physiology

Background:

• Catecholamine-induced desensitization of beta-adrenergic receptors is a known phenomenon.
• Surgical stress can lead to increased endogenous catecholamines, potentially causing receptor desensitization.

Purpose of the Study:

• To investigate whether intraoperative adrenergic activation during surgery leads to beta-adrenergic receptor desensitization.
• To examine alterations in human lymphocyte beta-adrenergic receptor density and affinity following anesthesia and non-cardiac surgery.

Main Methods:

• Studied 19 patients undergoing non-cardiac surgery with general anesthesia.
• Measured human lymphocyte beta-adrenergic receptor density and affinity using (-)125I-iodocyanopindolol binding.
• Monitored plasma levels of norepinephrine and epinephrine in a subset of patients.

Main Results:

• Patients with increased intraoperative catecholamines showed a significant postoperative increase in beta-receptor density (+25%) and decreased affinity for isoproterenol (-22%).
• No significant changes in beta-receptor density or affinity were observed in patients without intraoperative adrenergic activation.
• Postoperative heart rate response to catecholamines was attenuated in patients with adrenergic activation and decreased receptor affinity, indicating hyporesponsiveness.

Conclusions:

• Perioperative adrenergic activation during surgery can alter beta-adrenergic receptors.
• This alteration may lead to changes in beta-adrenergic responsiveness in surgical patients.