Biomaterial Database

Coronary microvascular response to exogenously administered and endogenously released acetylcholine. 1992

K G Lamping, and W M Chilian, and C L Eastham, and M L Marcus

Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City 52242.

The objectives of the present study were first, to determine the coronary microvascular response to vagal stimulation and to compare it to exogenously administered acetylcholine, and second, to determine the microvascular response to larger doses of acetylcholine which preferentially increase subendocardial blood flow. In anesthetized cats and dogs, the left ventricular epicardial vasculature was visualized in mid-diastole with stroboscopic epi-illumination. Myocardial perfusion was measured with the radioactive microsphere technique. In cats microvascular diameters were measured at control and following bilateral vagal nerve stimulation (5-30 Hz) or left atrial infusion of acetylcholine (0.4-1.0 micrograms/kg/min). Aortic pressure and heart rate (A-V-sequential pacing) were maintained constant. Vagal stimulation (n = 13) increased myocardial perfusion by 25 +/- 9% (control: 161 +/- 17 ml/min x 100 g). Acetylcholine (n = 13) produced a similar increase in myocardial flow (control: 185 +/- 16 ml/min x 100 g, 30 +/- 9%). Both vagal stimulation and acetylcholine dilated all size arteries and arterioles (51-410 microns; 5 +/- 1% and 11 +/- 2%, respectively). In dogs intracoronary administration of acetylcholine (10 micrograms/min) that increased myocardial flow twofold (control: 129 +/- 7 ml/min x 100 g; 10 micrograms/min: 263 +/- 26 ml/min x 100 g) and increased the endo/epi flow ratio also dilated all vessel sizes. In conclusion, vagal stimulation and exogenously administered acetylcholine produce similar effects on the coronary microcirculation and dilate all size classes of arteries and arterioles in a similar manner. Intracoronary infusion of acetylcholine which preferentially increases subendocardial blood flow also dilates all size classes of microvessels. Thus, the ability of acetylcholine to preferentially increase subendocardial blood flow cannot be explained by a selective dilation of a particular size class of arterioles. These data suggest that neurally released acetylcholine can diffuse to the endothelial layer to release vasodilator substances in vivo.

UI	MeSH Term	Description	Entries
D007263	Infusions, Parenteral	The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.	Intra-Abdominal Infusions,Intraperitoneal Infusions,Parenteral Infusions,Peritoneal Infusions,Infusion, Intra-Abdominal,Infusion, Intraperitoneal,Infusion, Parenteral,Infusion, Peritoneal,Infusions, Intra-Abdominal,Infusions, Intraperitoneal,Infusions, Peritoneal,Intra Abdominal Infusions,Intra-Abdominal Infusion,Intraperitoneal Infusion,Parenteral Infusion,Peritoneal Infusion
D008297	Male		Males
D008833	Microcirculation	The circulation of the BLOOD through the MICROVASCULAR NETWORK.	Microvascular Blood Flow,Microvascular Circulation,Blood Flow, Microvascular,Circulation, Microvascular,Flow, Microvascular Blood,Microvascular Blood Flows,Microvascular Circulations
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D003326	Coronary Circulation	The circulation of blood through the CORONARY VESSELS of the HEART.	Circulation, Coronary
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005260	Female		Females
D006325	Heart Atria	The chambers of the heart, to which the BLOOD returns from the circulation.	Heart Atrium,Left Atrium,Right Atrium,Atria, Heart,Atrium, Heart,Atrium, Left,Atrium, Right
D006439	Hemodynamics	The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.	Hemodynamic