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ObjectiveThe aim of our study was to determine the central and peripheral autonomic nervous system profiles underlying anorexia nervosa (AN) syndrome, given that affected patients present with the opposite clinical profile to that seen in the hyperinsulinism syndrome.DesignWe measured blood pressure and heart rate, as well as circulating neurotransmitters (noradrenaline, adrenaline, dopamine, plasma serotonin, and platelet serotonin), using high-performance liquid chromatography with electrochemical detection, during supine resting, one minute of orthostasis, and after five minutes of exercise. In total, 22 AN patients (12 binge-eating/purging type and 10 restricting type) and age-, gender-, and race-matched controls (70 ± 10.1% versus 98 ± 3.0% of ideal body weight) were recruited.ResultsWe found that patients with AN had adrenal sympathetic overactivity and neural sympathetic underactivity, demonstrated by a predominance of circulating adrenaline over noradrenaline levels, not only during the supine resting state (52 ± 2 versus 29 ± 1 pg/mL) but also during orthostasis (67 ± 3 versus 32 ± 2 pg/mL, P < 0.05) and after exercise challenge (84 ± 4 versus 30 ± 3 pg/mL, P < 0.01).ConclusionConsidering that this peripheral autonomic nervous system disorder depends on the absolute predominance of adrenomedullary C1 adrenergic nuclei over A5 noradrenergic pontine nucleus, let us ratify the abovementioned findings. The AN syndrome depends on the predominance of overwhelming adrenal sympathetic activity over neural sympathetic activity. This combined central and autonomic nervous system profile contrasts with that registered in patients affected by hyperinsulinism, hypoglycemia, and bulimia syndrome which depends on the absolute predominance of neural sympathetic activity.

ObjectiveThe purpose of the trial was to examine the effects of amantadine, a N-methyl-D-aspartate (NMDA) antagonist, on the oral glucose tolerance test (OGTT) plus insulin, glucagon and neurotransmitters circulating levels. Previous findings showed that hyperinsulinism and type 2 diabetes are positively associated with neural sympathetic and adrenal sympathetic activities, respectively. These peripheral sympathetic branches depend on the pontine (A5-noradrenergic) and the rostral ventrolateral (C1-adrenergic) medullary nuclei. They are excited by glutamate axons which act at NMDA postsynaptic receptors.Research design and methodsOne OGTT plus placebo and one OGTT plus oral amantadine test were carried out two weeks apart in 15 caucasic normal voluntary humans. Noradrenaline, adrenaline, dopamine, plasma-free serotonin, platelet serotonin, glucose, glucagon, and insulin were measured throughout the 180-minute testing period.ResultsMaximal reductions of plasma glucose and glucagon plus exacerbated insulin rises were significantly greater throughout the oral glucose plus amantadine test than those registered throughout the oral glucose plus placebo challenge. The above findings were paralleled by greater than normal noradrenaline/adrenaline plasma ratio increases. In addition, maximal reductions of the platelet serotonin and plasma serotonin circulating values contrasted with the normal rises of these parameters, always registered during the glucose load plus placebo challenge.ConclusionThis study supports the theory that amantadine might be a powerful antidiabetic tool and could be added to the therapeutic arsenal against type 2 diabetes.

Considering that glutamatergic axons innervate the C1(Ad) medullary nuclei, which are responsible for the excitation of the peripheral adrenal glands, we decided to investigate catecholamines (noradrenaline, adrenaline and dopamine) plus indolamines (plasma serotonin and platelet serotonin) at the blood level, before and after a small oral dose of amantadine, a selective NMDA antagonist. We found that the drug provoked a selective enhancement of noradrenaline plus a minimization of adrenaline, dopamine, plasma serotonin and platelet serotonin circulating levels. Significant enhancement of diastolic blood pressure plus reduction of systolic blood pressure and heart rate paralleled the circulating parameter changes. The above findings allow us to postulate that the drug was able to enhance the peripheral neural sympathetic activity. Minimization of both adrenal sympathetic and parasympathetic activities was also registered after the amantadine challenge. The above findings supported the postulation that this drug should be a powerful therapeutic tool for treating diseases affected by adrenal sympathetic hyperactivity.

Background:We have demonstrated that anorexia nervosa is underpinned by overwhelming adrenal sympathetic activity which abolishes the neural sympathetic branch of the peripheral autonomic nervous system. This physiological disorder is responsible for gastrointestinal hypomotility, hyperglycemia, raised systolic blood pressure, raised heart rate, and other neuroendocrine disorders. Therefore, we prescribed neuropharmacological therapy to reverse this central and autonomic nervous system disorder, in order to normalize the clinical and neuroendocrine profile. Methods: The study included 22 female patients with anorexia nervosa (10 restricted type, 12 binge-eating type) who received three months of treatment with amantadine 100 mg/day. We measured blood pressure, heart rate, and circulating neurotransmitters, (noradrenaline, adrenaline, dopamine, platelet serotonin, free plasma serotonin) during supine resting, one minute of orthostasis, and a five-minute exercise test before and after one, two, and three months of treatment with amantadine, a drug which abrogates adrenal sympathetic activity by acting at the C1(Ad) medullary nuclei responsible for this branch of the peripheral sympathetic activity. Results: We found the amantadine abolished symptoms of anorexia nervosa from the first oral dose onwards. Normalization of autonomic and cardiovascular parameters was demonstrated within the early days of therapy. Abrupt and sustained increases in the plasma noradrenaline:adrenaline ratio and disappearance of abnormal plasma glucose elevation were registered throughout the three-month duration of the trial. Significant and sustained increases in body weight were documented in all cases. No relapses were observed. Conclusion: We have confirmed our previously published findings showing that the anorexia nervosa syndrome depends on the hypomotility of the gastrointestinal tract plus hyperglycemia, both of which are triggered by adrenal sympathetic hyperactivity. The above neuroendocrine plus neuroautonomic and clinical disorders which underpinned anorexia nervosa were abruptly suppressed since the first oral dose of amantadine, a drug able to revert the C1(Ad) over A5(NA) pontomedullary predominance responsible for adrenal and neural sympathetic activity, respectively.