Epinephrine elicits an adrenotropic response in muscle tissue (through B-adrenoreceptors), conferring an increased sensitivity of the individual muscle spindles to the stretch reflex mechanism, thereby increasing the amplitude of physiological tremor.

Okay, that's a start, but is there any more information as to how this hypersensitivity is brought about? Molecules involved, signalling pathways, etc? Or at least a good review to read about it? I have found that the literature is fairly opaque, and that the precise mechanism may not be known. And what is the status of spindle hypersensitivity mechanism--proven, conjectured, etc? Sometimes conjectures, through time, seem to acquire the status of "truth," I have found.