[Role of the fusimotor system in regulating shivering]

Spontaneously active gamma-motoneurons were found in muscles of the cat during shivering. The activity of these gamma-motoneurons could be increased by stimulation of thermoreceptors of the subcutaneous vessels and nociceptors. Administration of oxotremorine, nicotin, phentolamine, isoprenaline, and seduxene into the 3rd brain ventricle suppressed the shivering but did not change the firing rate of the gamma-motoneurons. The fusomotor system seems to participate in the segmentary activation of shivering, but not in its supraspinal control.