Neuropharmacological investigations in the stiff-man syndrome.
In a patient with the stiff-man syndrome, abnormal exteroceptive reflexes in hand and arm muscles were used as a tool for investigating the effects of various centrally acting adrenergic drugs by means of acute testing. Clonidine, tizanidine and methamphetamine induced reflex suppression whereas reserpine had a biphasic effect: transient reflex suppression and delayed reflex enhancement. The drug actions on the reflexes paralleled to some degree those on the muscle stiffness. It is concluded that alpha-adrenergic stimulation leads to reflex suppression and muscular relaxation, whereas alpha-adrenergic blockade has the opposite effect. Correspondingly, long-term oral treatment with the alpha-stimulator, tizanidine, proved successful. The hypothesis is put forward that a noradrenergic system which exerts a net inhibitory influence on muscle tone and on exteroceptive reflexes plays an important role in the pathogenesis of the stiff-man syndrome.
D000320:Adrenergic Fibers / Q000502:physiology; D002493:Central Nervous System Diseases / Q000503:physiopathology*; D003000:Clonidine / Q000031:analogs & derivatives; D003975:Diazepam; D005260:Female; D006801:Humans; D008694:Methamphetamine; D009127:Muscle Rigidity / Q000503:physiopathology*; D012021:Reflex, Abnormal / Q000503:physiopathology*; D012110:Reserpine; D013577:Syndrome
D008694:Methamphetamine; C023754:tizanidine; D012110:Reserpine; D003000:Clonidine; D003975:Diazepam