Regulation of putative Ca/sup 2 +/ channels in the brain

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6401345

Skattebol, A

Ca/sup 2 +/ entry mechanisms were studied in a variety of neuronal preparations. In synaptosomes and intact brain cells K/sup +/-induced Ca/sup 2 +/ entry is a biphasic process. Highest density of both processes is found in the hippocampus and the lowest in the cerebellum. The slow second phase shows no regional distribution, is abolished in Na/sup +/ free medium and is antagonized by 3,4-dichlorobenzamil. It therefore likely represents Ca/sup 2 +/ influx through the Na/sup +//Ca/sup 2 +/ exchanger. The chronic treatment of rats with atropine or diisopropyl phosphororfluoridate (DFP) led to an increase or decrease of 30% and 50% respectively, in the number of muscarinic receptors in the brain. In a similar fashion chronic administration of propranolol increased ..beta..-adrenoceptors 69% and 50% in brain and heart respectively. Isoproterenol administration decreased ..beta..-adrenoceptors by 50% in heart, but had no effect in the brain. None of these protocols had an effects on the number of Ca/sup 2 +/ channel binding sites as detected by (/sup 3/H)nimodipine. Ethanol inhibits the first phase of synaptosomal /sup 45/Ca/sup 2 +/ uptake to a greater extent than the second phase. /sup 45/Ca/sup 2 +/ uptake in PC12 cells is inhibited in a similar fashion to that of the first phase. Chronic exposure to ethanol led to a 44% increase in /sup 45/Ca/sup 2 +/ uptake and a 38% increase in binding sites. This suggests that long-term antagonism of Ca/sup 2 +/ channels may lead to an increase in their numbers.

• Research Organization: State Univ. of New York, Buffalo (USA)
• OSTI ID: 6401345
• Country of Publication: United States
• Language: English

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550201 -- Biochemistry-- Tracer Techniques
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALCOHOLS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOLOGICAL EFFECTS
BODY
BRAIN
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CENTRAL NERVOUS SYSTEM
CHEMISTRY
CHRONIC EXPOSURE
DAYS LIVING RADIOISOTOPES
DRUGS
ETHANOL
EVEN-ODD NUCLEI
HYDROXY COMPOUNDS
INHIBITION
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
NERVES
NERVOUS SYSTEM
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RECEPTORS
SYMPATHOMIMETICS
TRACER TECHNIQUES
UPTAKE