Related Experiment Video
Updated: Jun 21, 2026

Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention
Published on: October 16, 2013
Opioid mu-receptors in medullary raphe region affect the hypoxic ventilation in anesthetized rats
Zhenxiong Zhang1, Fadi Xu, Cancan Zhang
1Pathophysiology Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM 87108, USA.
Abstract:
Opioids can attenuate the peripheral chemoreceptor-mediated hypoxic ventilatory response (HVR) by acting on central mu-type opioid receptors. Since the medullary raphe region (MRR) expresses abundant mu-receptors and participates in modulating HVR, we tested the role of mu-receptors within the caudal, medial, and rostral MRR (cMRR, mMRR, and rMRR) in modulating the HVR. We recorded cardiorespiratory activities and their responses to isocapnic hypoxia in anesthetized rats before and after local microinjection of DAMGO into the MRR, and intravenous administration of DAMGO (100 microg/kg) alone or coupled with a previous local injection of CTAP. Microinjecting DAMGO into the cMRR or mMRR but not the rMRR significantly attenuated the HVR. However, systemic DAMGO-induced HVR attenuation was not significantly affected by pretreating the cMRR and mMRR with CTAP. Our data suggest that cMRR and mMRR mu-receptors are capable of depressing the HVR, while their contribution to the attenuated HVR by systemic DAMGO is limited.
Related Concept Videos
Opioid Receptors: Overview
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Analgesia and Pain Management
Chemical Factors Affecting Respiration Centers
CO2 has a potent influence on respiration and is strictly regulated. Under...
Parenteral Anesthetics: Overview
Neural Control of Respiration
Respiratory Centers in the Brainstem
Two primary areas comprise the respiratory center: the medullary respiratory center in the medulla oblongata and the pontine respiratory group in the pons. The...

