New findings on the neuropathology of multiple system atrophy.

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New findings on the neuropathology of multiple system atrophy.

Benarroch EE.

Neurophysiological Laboratory, Department of Neurology, Mayo Clinic,

Rochester, MN 55905, USA. benarroch.eduardo@...

Multiple system atrophy (MSA) provides a typical example of the

integrative role of the central autonomic network in controlling

cardiovascular, respiratory, bladder and gastrointestinal functions.

There is increasing evidence that neurochemically defined neuronal

groups of the brainstem are selectively affected in MSA to a much

greater degree than in Parkinson's disease. These include the

catecholaminergic neurons of the rostral ventrolateral medulla (C1

group) which project to the intermediolateral cell column and are

involved in modulation of sympathetic vasomotor outflow, and

noradrenergic neurons of the caudal ventrolateral medulla (A1 group)

projecting to the magnocellular nuclei of the hypothalamus and

regulating vasopressin (AVP) release. Loss of these groups of neurons

may, at least in part, explain the development of orthostatic

hypotension, baroreflex dysfunction, and impaired reflex AVP release

in response to hypotension. There is preliminary evidence that

cardiovagal neurons of the ventrolateral portion of the nucleus

ambiguus, distinct from the branchimotor neurons of the compact

region, may also be affected in MSA. Loss of cholinergic neurons in

the medullary arcuate nucleus, considered by some to be the

homologous to the central chemosensitive region of the ventral

medullary surface, may contribute to disturbances in automatic

ventilation, particularly during sleep, in patients with MSA.

PMID: 11911503 [PubMed - in process]