Document Detail


Clinical biochemistry of epilepsy. II. Observations on two types of epileptiform convulsions induced in rabbits with corticotropin.
MedLine Citation:
PMID:  221137     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We propose than an alarm mechanism is operative in animals, designed to regulate neuromuscular irritability by regulating [Ca2+]. Epinephrine or corticotropin (ACTH), injected intramuscularly into animals, causes a hypercitricemia, resulting in decreased [Ca2+]. This increases muscular excitability to facilitate escape. To avoid over reaction, [Cl-] is shifted into the plasma without a concomitant shift of Na+, thus generating an acidosis and an increase in ionization of Ca. Plasma pH, pCO2, total CO2, and [K+] decrease, and [Mg2+] increases. The acidosis, decrease in K+, and increase in [Mg2+] serve to counteract the effect of the decrease in [Ca2+], to protect against tetany. In the rabbit the hypercitricemia observed upon ACTH administration is accompained by a severe hypocalcemia and drop in blood pressure, resluting in tetanic convulsions. This seems to indicate calcitonin release, independent of the hypercitricemia. Thyroidectomized rabbits show only mild hypocalcemia when given ACTH, but develop a severe acidosis and typical grand mal epileptiform seizures. Administration of ACTH and then calcitonin to the goat, an animal resistant to the effects of ACTH alone, simulates the effect observed in the rabbit with respect to changes in blood components and blood pressure. Changes in the blood in the goat and rabbit resemble those in humans before an epileptic seizure. alpha-Melanotropin, containing a portion of the ACTH sequence, reacts in a manner similar to ACTH but more rapidly.
Authors:
S Natelson; D J Miletich; C F Seals; D J Visintine; R F Albrecht
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical chemistry     Volume:  25     ISSN:  0009-9147     ISO Abbreviation:  Clin. Chem.     Publication Date:  1979 Jun 
Date Detail:
Created Date:  1979-08-29     Completed Date:  1979-08-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9421549     Medline TA:  Clin Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  898-913     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adrenocorticotropic Hormone / pharmacology*
Animals
Blood Chemical Analysis
Blood Pressure
Calcitonin / pharmacology
Calcium / blood,  pharmacology
Chlorides / blood
Epilepsy / chemically induced,  physiopathology*
Epinephrine / pharmacology
Fasting
Goats
Humans
Rabbits
Seizures
Chemical
Reg. No./Substance:
0/Chlorides; 51-43-4/Epinephrine; 7440-70-2/Calcium; 9002-60-2/Adrenocorticotropic Hormone; 9007-12-9/Calcitonin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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