[Tremor following intracerebral carbachol injection. 1.Carbachol sensitivity of various brain structures]

Tremor produced by intracerebral injection of carbachol. I. Susceptibility of different brain areas to carbachol Microinjections of carbachol into the lateral ventricle of rats caused tremor depending on dose. Intensity and duration of motor effects after injection of carbachol (30 mug/3 mul bilateral) into different brain areas were found to depend on localization: strongest tremor was elicited by injections into the nucleus caudatoputamen and cortex cerebri, moderate tremor by administration into the substantia nigra reticularis, globus pallidus and thalamic brain regions. Target areas of mean sensitivity were demonstrated in more rostral and caudal parts of the formatio reticularis. The injection of carbachol into the nucleus ruber, nucleus linearis and substantia nigra compacta brought about lowest tremor values. Ablation of the site of injection from the remaining brain abolished tremor induced by carbachol contrary to the tremor induced by oxotremorine.