Total chemical sympathectomy in experimental animals results in loss of shivering and nonshivering thermogenesis, and death within a few hours.
Further evidence suggesting that abnormal sympathetic activity may cause pain comes from reports of pain following sympathectomy. This has occurred after stellate ganglion block and lumbar sympathectomy.
A similar reduction of fat mobilization from fat depots occurs after VMH lesions, as after local sympathectomy, suggesting that the sympathetic pathway to the adipose tissue runs through the VMH.
Bray and York hypothesize that the change in energy balance in animals after VMH lesions is a result of autonomic dysequilibrium. The sympathetic outflow is reduced and the parasympathetic outflow increased. This shift in balance results in hyperinsulinemia and altered metabolic pathways leading to obesity. During the digestion and metabolism of a meal, the autonomic nervous system provides important (but not sole) feedback control on satiety.
The Nervous System and Adipose Tissue, By Katharine Dalziel, MD, MBBS, MRCP
Clinics in Dermatology
October-December 1989, Volume 7, Number 4, pages 62-77