Biomaterial Database

Pulmonary vasodilator responses to vagal stimulation and acetylcholine in the cat. 1983

P A Nandiwada, and A L Hyman, and P J Kadowitz

Responses to vagal stimulation and acetylcholine were investigated in the feline pulmonary vascular bed under conditions of controlled pulmonary blood flow and constant left atrial pressure. Under baseline conditions, electrical stimulation of vagal efferent fibers increases lobar arterial pressure. However, when vasoconstrictor tone was increased, a depressor response was unmasked. The pressor response under baseline conditions and the depressor response under enhanced tone conditions were blocked by phenoxybenzamine and atropine. These data suggest that, in the cat, the vagus is composed of efferent fibers from both the sympathetic and parasympathetic systems. After treatment with 6-hydroxydopamine to destroy the integrity of the sympathetic system, vagal stimulation caused significant frequency-dependent decreases in lobar arterial pressure when lobar vascular tone was increased by infusion of a stable prostaglandin endoperoxide analog or ventilatory hypoxia. Injections of acetylcholine also caused significant dose-related decreases in lobar arterial pressure when lobar vascular resistance was elevated. Depressor responses to vagal stimulation and acetylcholine in 6-hydroxydopamine-treated animals were blocked by atropine and enhanced by physostigmine. Decreases in lobar arterial pressure in response to vagal stimulation in 6-hydroxydopamine-treated animals with enhanced tone were blocked by hexamethonium, whereas responses to injected acetylcholine were not altered by the ganglionic blocking agent. Decreases in lobar arterial pressure in response to vagal stimulation and acetylcholine were similar when the lung was ventilated and when the left lower lobe bronchus was obstructed. In addition, responses to vagal stimulation were similar when systemic arterial pressure was decreased to the level of pressure in the perfused lobar artery. Responses to acetylcholine were not altered after treatment with 5,8,11,14-eicosatetraynoic acid, a lipoxygenase inhibitor. The present data suggest that the feline pulmonary vascular bed is functionally innervated by cholinergic nerves and that vagal stimulation dilates the pulmonary vascular bed by releasing acetylcholine which acts on muscarinic receptors in pulmonary vessels.

UI	MeSH Term	Description	Entries
D007022	Hypotension	Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.	Blood Pressure, Low,Hypotension, Vascular,Low Blood Pressure,Vascular Hypotension
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D008297	Male		Males
D010830	Physostigmine	A cholinesterase inhibitor that is rapidly absorbed through membranes. It can be applied topically to the conjunctiva. It also can cross the blood-brain barrier and is used when central nervous system effects are desired, as in the treatment of severe anticholinergic toxicity.	Eserine
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
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
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
D006892	Hydroxydopamines	Dopamines with a hydroxy group substituted in one or more positions.	Hydroxydopamine
D000109	Acetylcholine	A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.	2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine