Exaggerated responses to drugs following nervous system lesions were described in the medical literature more than a century ago. Although the phenomenon of supersensitivity is still not completely understood, studies in experimental animals have clarified the distinction between denervation and decentralization (for review see Trendelenberg, 1963). These characteristic pharmacologic abnormalities form the basis for distinguishing pre-, and post-ganglionic noradrenergic involvement.
Chronic postgangliionic denervation increases the pressor response to NA, while the effects of indirect symphatomimetics are reduced. Decentralization causes more modest changes in the blood pressure response and is not associated with loss of neuronal NA stores; the increase in pressor sensitivity is non-specific.
Disorders of the Autonomic Nervous System
By David Robertson, Italo Biaggioni
Published by Informa Health Care, 1995
ISBN 3718651467, 9783718651467