Clinical autonomic research : official journal of the Clinical Autonomic Research Society
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The insular cortex is involved in cardiac regulation. The left insula is predominantly responsible for parasympathetic cardiovascular effects. ⋯ In addition, phase relationships between heart rate and blood pressure were disturbed, implying a disruption of oscillators involved in cardiovascular control. The insula appears to be involved in human heart rate regulation and damage to it may encourage a pro-arrhythmic state.
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Comparative Study Clinical Trial
Cardiovascular adjustments and pain during repeated cold pressor test.
The cold pressor test is used in the clinical testing of the autonomic nervous system. However, little is known about changes in the autonomic control of the cardiovascular system during repeated challenge with cold. Heart rate (HR), respiratory sinus arrhythmia (RSA), T-wave amplitude of ECG (TWA), blood pressure, body temperature and perceived pain were recorded in 18 male subjects during three CPTs which consisted of four minutes immersion of the left hand into cold water at 1 degree C. ⋯ RSA increased in the second and third cold challenge during paced breathing at 0.1 Hz only. A decrease in body temperature (0.48 degree C) at the end of the experiment correlated marginally with HR changes. Our study shows that sustained cardiovascular changes are induced by the first challenge with cold, and persist or increase with repeated cold pressor tests.
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Abnormal regulation of the large cranial arteries seems to play a significant role in the mechanisms of migraine pain. Thus, vasodilatation of extra- and intracranial conductance arteries has been described both during spontaneous migraine attacks and during experimentally provoked vascular headaches. The regulation of the diameter of these arteries is complex and involves autonomic, trigeminovascular, endothelial and humoral mechanisms. ⋯ As the enzyme responsible for nitric oxide synthesis is present in parasympathetic nerve endings around cerebral arteries, this supports a role for the parasympathetic nervous system in migraine. In addition, vasoactive transmitters released from perivascular trigeminal nerve endings may be implicated. Several of these aspects are closely linked to the presumed mechanisms of action of modern migraine therapeutics.
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A case of hemifacial atrophy (Parry-Romberg disease) is discussed. Electrophysiological and immunological studies were performed. ⋯ Immunological evidence favoured this possibility and demonstrated possible involvement of the noradrenergic system. Hyperactivity of the brain stem sympathetic centres, possibly caused by an autoimmune process, may be the primary cause of the cutaneous and subcutaneous atrophy in Parry-Romberg disease.
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Cardiovascular diseases are the leading causes of death in the United States, with hypertension being amongst the most prevalent of the cardiovascular risk factors. Improvement of hypertension management has, in consequence, received much attention. Extensive pre- and post-marketing experience with the transdermal formulation of clonidine marketed in the USA in the mid-1980s has now been accumulated. ⋯ Minor skin reactions occur at the site of application of the transdermal patch with moderate frequency. Adherence to transdermal clonidine therapy is high, and patients commonly prefer it to oral therapy. Transdermal administration of clonidine is a useful therapeutic advance in the long-term management of hypertension.