pituitrin and Multiple-System-Atrophy

We sought to determine whether there is differential involvement of different groups of hypothalamic arginine-vasopressin (AVP) synthesizing neurons in multiple system atrophy (MSA). Hypothalamus was obtained from five subjects with clinical diagnosis of MSA confirmed neuropathologically and five age-matched controls. Sections were immunostained for AVP, and cells with visible nuclei were counted in the posterior portion of the paraventricular nucleus (PVNp), supraoptic nucleus (SON), magnocellular PVN and suprachiasmatic nucleus (SCN). Sections of the hypothalamus and medulla were also immunostained for tyrosine hydroxylase (TH). There was a significant loss of AVP neurons in the PVNp in MSA compared with controls (17 +/- 3 versus 59 +/- 10 cells/section, P < 0.01). There was preservation of AVP- and TH-immunoreactive neurons in the SON and magnocellular PVN in all MSA cases. In contrast, there was marked depletion of TH-immunoreactive fibres innervating these magnocellular AVP neurons, coincident with a loss of neurons in the A1 area (6 +/- 1 versus 13 +/- 1 cells/section, P < 0.01). There was loss of AVP neurons in the SCN in MSA compared with control cases (14 +/- 3 versus 71 +/- 16 cells/section, P < 0.02). Our results indicate that, in MSA, loss of AVP neurons in the PVNp may contribute to sympathetic failure, whereas loss of catecholaminergic input from the brainstem to the magnocellular AVP neurons may contribute to impaired AVP secretion in response to orthostatic stress. Loss of AVP neurons in the SCN may contribute to impaired circadian regulation of endocrine and autonomic functions.

Topics: Aged; Aged, 80 and over; Case-Control Studies; Female; Humans; Hypothalamus, Anterior; Image Processing, Computer-Assisted; Immunohistochemistry; Male; Middle Aged; Multiple System Atrophy; Neurons; Paraventricular Hypothalamic Nucleus; Suprachiasmatic Nucleus; Supraoptic Nucleus; Tyrosine 3-Monooxygenase; Vasopressins

Although autonomic failure (AF) is a critical symptom of multiple system atrophy (MSA), it may not appear until late in the disease process.. To clarify whether a detailed investigation of the autonomic nervous system in patients with MSA without overt AF demonstrates latent lesions of central cardiovascular control circuits and facilitates the early diagnosis of MSA.. Autonomic function tests, and plasma noradrenaline (NA) and vasopressin (AVP) responses to head-up tilt (HUT), were studied in 12 patients with MSA with AF (probable MSA), 12 with MSA without overt AF (possible MSA), and 24 controls.. Abnormalities of cardiovascular autonomic function tests were prominent in the first group but mild in the second. Plasma NA and AVP increments upon HUT differed significantly among all three groups.. These results indicate that probable MSA involves diffuse degeneration of central cardiovascular control circuits. On the other hand, the discrepancies in possible MSA suggest a vulnerability of the noradrenergic (A1) neurones of the caudal ventrolateral medulla that are involved in AVP secretion. This finding also suggests that AVP increment may be useful as a diagnostic tool in the early stages of MSA.

Topics: Aged; Autonomic Nervous System; Biomarkers; Disease Progression; Female; Humans; Male; Medulla Oblongata; Middle Aged; Multiple System Atrophy; Pressoreceptors; Vasopressins

We describe the first case of Shy-Drager syndrome diagnosed on the basis of intraoperative hemodynamic changes. The initial hypertension in the supine position followed by severe hypotension after hydralazine administration, ultimately responsive to vasopressin, led to a diagnosis of Shy-Drager syndrome. We suggest that vasopressin may be the drug of choice in patients with Shy-Drager syndrome with refractory hypotension.

Topics: Adrenergic beta-Antagonists; Aged; Hemodynamics; Humans; Hypotension; Intraoperative Complications; Labetalol; Leg Ulcer; Male; Monitoring, Intraoperative; Multiple System Atrophy; Phenylephrine; Shy-Drager Syndrome; Vasoconstrictor Agents; Vasopressins