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Updated: Aug 15, 2026

Assessing Murine Resistance Artery Function Using Pressure Myography
Published on: June 7, 2013
Comparative effects of acetylcholine on the reptilian and mammalian aortae
1Department of Pharmacology, Obafemi Awolowo College of Health Sciences, Ogun State University Teaching Hospital, Sagamu, Nigeria.
Abstract:
Responses of the lizard and the rabbit thoracic aortae to acetylcholine were studied. Acetylcholine (ACh) (10 nM-100 microM), carbachol (10 nM-50 microM) and PGF2 alpha (100 nM-100 microM) produced concentration-dependent contractions of the lizard thoracic aorta (LTA) with rapid tachyphylaxis. On the other hand, acetylcholine and carbachol relaxed the rabbit thoracic aorta (RTA) dose-dependently. There was no tachyphylaxis. Tachyphylaxis in the LTA was prevented by indomethacin (1 microM) or by rubbing the endothelium. Endothelial removal abolished ACh-induced relaxation of the RTA. Relaxation of the RTA and contractions of LTA were blocked by atropine, pirenzepine, acetoxy-N-methyl-piperidine methbromide (4-DAMP) and diltiazem. Removal of the endothelium rendered RTA insensitive to ACh. However, ACh-induced contractions of the LTA were not so influenced by removal of endothelial cells. It is concluded that the lizard thoracic aorta releases a metabolite of arachidonic acid that mediates tachyphylaxis. Relaxation of the RTA after ACh is mediated via the release of endothelium-dependent relaxing factor.
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