Norepinephrine and veratrine stimulated formation of inositol phosphates in rat brain slices
Stimulation of phosphoinositide (PIn) hydrolysis by depolarization with veratrine was compared to that produced by stimulation of alpha/sub 1/ adrenoceptors by norepinephrine (NE). The PIns in rat cerebral cortex were labelled with /sup 3/H-myoinositol and the effects of the drugs on the formation of the three /sup 3/H-inositol phosphates (IP, IP2, IP3) were determined. The amounts of IP and IP2 formed by a maximal concentration of veratrine were about 50% of that formed by a maximal concentration of NE while the amount of IP3 formed after stimulation by veratrine was only about 10% of that produced by NE. The increase in IP was linear with time (30 min) for both NE and veratrine. IP2 and IP3 stimulation by veratrine reached a maximum at 5 min whereas that produced by NE continued to increase for 30 min. Blockade of voltage dependent calcium channels with manganese produced nearly complete antagonism of the veratrine response while only partially antagonizing the NE response. NE-induced IP2 formation was less sensitive to manganese than IP or IP3. These data suggest that veratrine causes hydrolysis of either a different pool of PIn or that the hydrolysis occurs by a different mechanism compared to NE. The data also suggest that IP2 may be produced directly from phosphatidylinositol 4-phosphate rather than solely as a metabolite of IP3.
- Research Organization:
- Univ. of Kansas, Lawrence
- OSTI ID:
- 6942900
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NORADRENALINE
BIOCHEMICAL REACTION KINETICS
PHOSPHOLIPIDS
BIOSYNTHESIS
BRAIN
HYDROLYSIS
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ADRENAL HORMONES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
DECOMPOSITION
DRUGS
ESTERS
HORMONES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIPIDS
LYSIS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
SOLVOLYSIS
STEROID HORMONES
SYMPATHOMIMETICS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques