Prejunctional inhibition of norepinephrine release caused by acetylcholine in the human saphenous vein
We performed experiments to determine whether or not acetylcholine exerts a prejunctional inhibitory effect on adrenergic neurotransmission in the human blood vessel wall. Rings of human greater saphenous veins were prepared 2 to 15 hours after death and mounted for isometric tension recording in organ chambers filled with Krebs-Ringer solution. Acetylcholine depressed contractile responses to electric activation of the sympathetic nerve endings significantly more than those to exogenous norepinephrine; the relaxations caused by the cholinergic transmitter were antagonized by atropine. Helical strips were incubated with (/sub 3/H)norepinephrine and mounted for superfusion. Electric stimulation augmented the fractional release of labeled norepinephrine. Acetylcholine caused a depression of the evoked /sub 3/H release which was antagonized by atropine but not by hexamethonium. These experiments demonstrate that, as in animal cutaneous veins, there are prejunctional inhibitory muscarinic receptors on the adrenergic nerve endings in the human saphenous vein. By contrast, the human vein also contains postjunctional inhibitory muscarinic receptors.
- OSTI ID:
- 5612943
- Journal Information:
- Circ. Res.; (United States), Journal Name: Circ. Res.; (United States) Vol. 49:2; ISSN CIRUA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
ADRENAL HORMONES
ALKALOIDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
ATROPINE
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BLOOD VESSELS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
DRUGS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ESTERS
HORMONES
INHIBITION
LABELLED COMPOUNDS
MAMMALS
MAN
NERVES
NERVOUS SYSTEM
NEUROREGULATORS
NORADRENALINE
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PHYSICAL PROPERTIES
PRIMATES
QUATERNARY COMPOUNDS
RECEPTORS
STEROID HORMONES
SYMPATHOMIMETICS
TRITIUM COMPOUNDS
VEINS
VERTEBRATES