Clinical biochemistry of epilepsy. II. Observations on two types of epileptiform convulsions induced in rabbits with corticotropin
| Autor: | Ronald F. Albrecht, C F Seals, D J Miletich, David J. Visintine, S Natelson |
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| Rok vydání: | 1979 |
| Předmět: |
endocrine system
medicine.medical_specialty Tetany business.industry Biochemistry (medical) Clinical Biochemistry medicine.disease pCO2 Epilepsy Blood pressure Endocrinology Epinephrine Calcitonin Internal medicine medicine Epileptic seizure medicine.symptom business hormones hormone substitutes and hormone antagonists Acidosis medicine.drug |
| Zdroj: | Clinical Chemistry. 25:898-913 |
| ISSN: | 1530-8561 0009-9147 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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