Norepinephrine uptake by rat jejunum: Modulation by angiotensin II

Journal Article · Mon Feb 01 00:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6868172

Suvannapura, A; Levens, N R ^[1]

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1. CIBA-GEIGY Corp., Summit, NJ (USA)

Angiotensin II (ANG II) is believed to stimulate sodium and water absorption from the small intestine by enhancing sympathetic nerve transmission. This study is designed to determine whether ANG II can enhance sympathetic neurotransmission within the small intestine by inhibition norepinephrine (NE) uptake. Intracellular NE accumulation by rat jejunum was concentration dependent and resolved into high- and low-affinity components. The high-affinity component (uptake 1) exhibited a Michaelis constant (K{sub m}) of 1.72 {mu}M and a maximum velocity (V{sub max}) of 1.19 nmol {center dot} g{sup {minus}1} {center dot} 10 min{sup {minus}1}. The low-affinity component (uptake 2) exhibited a K{sub m} of 111.1 {mu}M and a V{sub max} of 37.1 nmol {center dot} g{sup {minus}1} {center dot} 10 min{sup {minus}1}. Cocaine, an inhibitor of neuronal uptake, inhibited the intracellular accumulation of label by 80%. Treatment of animals with 6-hydroxydopamine, which depletes norepinephrine from sympathetic terminals, also attenuated NE uptake by 60%. Thus accumulation within sympathetic nerves constitutes the major form of ({sup 3}H)NE uptake into rat jejunum. ANG II inhibited intracellular ({sup 3}H)NE uptake in a concentration-dependent manner. At a dose of 1 mM, ANG II inhibited intracellular ({sup 3}H)NE accumulation by 60%. Cocaine failed to potentiate the inhibition of ({sup 3}H)NE uptake produced by ANG II. Thus ANG II appears to prevent ({sup 3}H)NE accumulation within rat jejunum by inhibiting neuronal uptake.

• OSTI ID: 6868172
• Journal Information: American Journal of Physiology; (USA), Vol. 254:2; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ADRENALINE
UPTAKE
ANGIOTENSIN
BIOLOGICAL EFFECTS
INTESTINAL ABSORPTION
BIOCHEMICAL REACTION KINETICS
TRITIUM COMPOUNDS
BIOELECTRICITY
COCAINE
DOSE-RESPONSE RELATIONSHIPS
NERVES
RATS
SMALL INTESTINE
ABSORPTION
ADRENAL HORMONES
ALKALOIDS
ANESTHETICS
ANIMALS
ANTIDEPRESSANTS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM AGENTS
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DIGESTIVE SYSTEM
DRUGS
ELECTRICITY
GASTROINTESTINAL TRACT
GLOBULINS
HYDROGEN COMPOUNDS
INTESTINES
KINETICS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PROTEINS
PSYCHOTROPIC DRUGS
REACTION KINETICS
RODENTS
SYMPATHOMIMETICS
VASOCONSTRICTORS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques