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), Vol. 49:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACETYLCHOLINE
BIOLOGICAL EFFECTS
NORADRENALINE
INHIBITION
ATROPINE
ELECTRIC CONDUCTIVITY
MAN
NERVES
RECEPTORS
TRITIUM COMPOUNDS
VEINS
ADRENAL HORMONES
ALKALOIDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BLOOD VESSELS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
DRUGS
ELECTRICAL PROPERTIES
ESTERS
HORMONES
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PHYSICAL PROPERTIES
PRIMATES
QUATERNARY COMPOUNDS
STEROID HORMONES
SYMPATHOMIMETICS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques