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Maturation of somatomotor responses to strychnine in the albino rat
Author(s) -
ENGELHARDT E.,
ESBÉRARD C. A.
Publication year - 1968
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1968.tb07046.x
Subject(s) - strychnine , neuroscience , biology , pharmacology
1 The maturation of the convulsogenic activity of the caudal brainstem and spinal cord in the developing albino rat was studied by intraperitoneal injections of strychnine sulphate. 2 The observed responses were classed as hyperexcitability and hypertonic responses, graded 1 to 4. The complete tonic seizure (grade 4 hypertonic reaction, strychnine tetanus, maximal response) was obtained in all age groups, from birth to adulthood. The responses were grouped in sequences, and two patterns were distinguished: an infant one (from birth to 3 weeks) and an adult one (from 3 weeks on). 3 All doses varied according to age. The curve obtained for the median convulsive dose falls into two parts: descending, from birth to 3 weeks, and ascending, from 3 weeks on. Each part corresponded to a sequence pattern, the descending one to the infant pattern, and the ascending one to the adult pattern. 4 From these patterns and the corresponding median effective doses, three stages of the convulsogenic maturation of the spinal cord were distinguished: immaturity, pharmacological maturity and convulsogenic maturity. 5 It is suggested that the mechanism responsible for the complete tonic seizure is fully functional from birth, while that responsible for clonic seizure only reaches full maturity at 3 weeks of age.