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A COMPARISON OF THE ACTIONS OF SOME DRUGS ON DECEREBRATE RIGIDITY, MUSCLE SPINDLE ACTIVITY AND α‐ADRENOCEPTORS
Author(s) -
MAXWELL D.R.,
SUMPTER EILEEN A.
Publication year - 1974
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.1476-5381.1974.tb09610.x
Subject(s) - decerebration , chemistry , decerebrate state , rigidity (electromagnetism) , muscle rigidity , pharmacology , anesthesia , endocrinology , reflex , medicine , stimulation , materials science , electric stimulation , composite material
1 The relative potencies of methotrimeprazine, (+)‐methotrimeprazine, (±)‐10‐(3‐dimethylamino‐2‐methylpropyl)‐2‐valeroyl phenothiazine hydrochloride (M & B 18,706) and (+)‐M & B 18,706 in reducing the pressor action of noradrenaline in the spinal cat, reducing intercollicular decerebrate rigidity, and muscle spindle afferent activity have been studied. 2 Methotrimeprazine was eight times as potent as (+)‐methotrimeprazine in reducing the pressor action of noradrenaline and six times as potent in reducing decerebrate rigidity. M & B 18,706 was also eight times as potent as (+)‐M & B 18,706 in reducing the pressor action of noradrenaline and six times as potent in reducing decerebrate rigidity. 3 For the above compounds and chlorpromazine there was a significant correlation between the effective doses for the inhibition of the pressor action of noradrenaline and for the reduction of decerebrate rigidity. 4 The doses which reduced decerebrate rigidity were similar to those that reduced muscle spindle afferent discharge. It is likely that these drugs reduce decerebrate rigidity by inhibiting fusimotor activity. 5 Desipramine increased decerebrate rigidity and increased spindle afferent discharge. 6 It is thought that the phenothiazine derivatives studied reduce decerebrate rigidity and spindle afferent discharge by inhibiting receptors for noradrenaline in the central nervous system.