Effects of M1 and M2 receptor agonists and blockers on dog respiration

Bing Yao, Xiao Qun Ge, Jia Lin Zheng, Wei Qin, Chun Fu Bian

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Aim: To study the effects of M1 and M2 receptor agonists and blockers on dog respiration. Methods: Using thoracic respiratory transducer and RM-86 multipurpose polygraph to determine respiratory rate (RR), tidal volume (TV), and minute ventilation volume (MVV), and DH-100G blood gas analysis instrument to analyze pO2, pCO2 and pH. Results: Pilocarpine (Pil, an M1-R subtype agonist) 0.5, 1, and 2 mg·kg-1 iv caused increases in RR, MVV, and pO2, and a decrease in pCO2. The excitatory effects of Pil were antagonized by pretreatment with pirenzepine (Pir, 3 mg·kg-1, iv) and scopolamine (Sco, 2 mg·kg-1, iv). The iv injections of a novel M2-R subtype agonist, 6β-acetoxy nortropane (6β-AN) 2, 5, and 20 μg·kg-1 caused decreases in RR, MVV, and pO2 and an increase of pCO2. The actions of 6β-AN were antagonized by iv treatment with AF-DX116 }11-2[[2-[(diethylamino)methyl]-1-piperidinyl]acetyl]-5,11-dihydro-6H [2,3-b][1,4]benzodiazepine-6-one, 0.5 mg·kg-1} and atropine (Atr, 2 mg·kg-1). Similar results were obtained with smaller doses of Pil (0.2, 0.4, and 0.8 mg·kg-1) and 6β-AN (0.25, 0.5, and 1 μg·kg-1) were injected into the vertebral artery. Pir and Sco also antagonized the excitatory effects of Pil, and AF-DX116 and Atr antagonized the inhibitory effects of 6β-AN on respiration. Conclusion: Stimulating M1-R of the respiratory center caused excitation of the respiration while stimulating the M2-R subtype caused inhibition of the respiration.

Original languageEnglish (US)
Pages (from-to)267-270
Number of pages4
JournalActa Pharmacologica Sinica
Issue number3
StatePublished - May 1996
Externally publishedYes


  • atropine
  • muscarinic receptors
  • nortropanes
  • pilocarpine
  • pirenzepine
  • res piration
  • scopolamine

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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