Testmeal Responses Following m-Chlorophenylpiperazine and L-Tryptophan in Bulimics and Controls

Abstract

A wealth of data support a role for serotonin (5-HT) function in the mediation of satiety responses, that are impaired in patients with bulimia nervosa. Testmeal results are presented in which 26 bulimic patients and 17 normal controls were given in randomized, double-blind-fashion, placebo, and the 5-HT agents m-chlorophenylpiperazine (m-CPP, 0.5 mglkg p.o.) and L-tryptophan (L-TRP, 100 mglkg I. V.). Three and one-half hours after drug administration, subjects were allowed to eat and lib from a standardized testmeal of 3,500 calories, after which postprandial vomiting was not allowed. M-CPP, but not L-TRP, significantly decreased meal size in the combined group, the controls, and to a lesser extent, the bulimics (p � .06). Maximum m-CPP Serotonergic manipulations are known to result in marked changes in feeding behaviors, particularly sati ety responses (Blundell 1977(Blundell , 1984(Blundell , 1986Blundell and Latham, 1978, 1982Latham and Blundell 1979;Samanin et al. 1982;Silverstone and Goodall 1986;Garattini et al., 1988Garattini et al., , 1989, which are dysfunctional in bulimic patients (Owen et al. 1985;Chiodo and Latimer 1986;Kissileff et al. 1986). Pharmacologic en hancement of 5-HT neurotransmission in animals and concentrations were inversely correlated to the number of calories consumed in the total group. Following m-CPP, there were significant decreases in carbohydrate, protein, and fat intake in the total group of subjects. There were also trends for decreased carbohydrate and protein intake in the bulimics following m-CPP. There were trends for both m-CPP and L-TRP to reduce fat intake in the controls. Differences in the effects between m-CPP and L-TRP are likely due to differential involvement of 5-HT receptor subtypes at presynaptic and postsynaptic sites. These studies in humans confirm reports in animals that m-CPP decreases food intake, including carbohydrates, protein, and fat in a mixed testmeal.

Is migraine related to the eating disorders?

“…Taken together, these data also suggest that migraine and the eating disorders, particularly BN, may share common pathophysiological mechanisms, perhaps involving 5-HT dysfunction (Brewerton et al, 1989(Brewerton et al, , 1990bBrewerton, Murphy, Lesem, Brandt, & Jimerson, 1992~). In particular, alterations of 5-HT function may predispose certain individuals to dysregulation of mood and anxiety, as well as vascular tone and pain.…”

“…There are several alterations in 5-HT function that have been reported in migraine and are reviewed elsewhere (Brewerton, Murphy, & Jimerson, 1988;Brewerton et al, 1990bBrewerton et al, , 1992Brewerton & George, 1!390;Eadie & Tyrer, 1985). Likewise, there have been a number of alterations in 5-HT function reported in BN, including blunted prolactin responses to both m-CPP (Brewerton et al, 1990b(Brewerton et al, , 1992b and 5-HTP (Goldbloom & Garfinkel, 1990), and increased platelet 5-HT uptake (Goldbloom & Garfinkel, 1990). Further research is necessary to delineate the similarities and differences between these disorders.…”

“…Furthermore, some migraine patients treated with the 5-HT antagonists methysergide or pizotofen have been reported to develop hyperphagia and weight gain (Blundell, 1977;Speight & Avery, 1972). Taken together, these data suggest a common pathophysiological relationship involving postsynaptic 5-HT dysfunction between these disorders (Brewerton et al, 1989(Brewerton et al, , 1990b(Brewerton et al, , 1992a. In order to further explore the possible relationship between eating disorders and migraine we assessed eating disorder pathology in a group of migraine patients being treated in a university neurology clinic.…”

Eating Disorders, Addictions and Substance Use Disorders

“…Patients with bulimic-spectrum disorders may binge on any type of foods, and the proportion of macronutrients in binge meals is no different from that of non-binge meals (Brewerton, Murphy, & Jimerson, 1994;. Patients with bulimic-spectrum disorders may binge on any type of foods, and the proportion of macronutrients in binge meals is no different from that of non-binge meals (Brewerton, Murphy, & Jimerson, 1994;.…”

The Psychoactive Effects of Aromatic Amino Acids

“…Brewerton et al [97] show that the administration of mchlorophenylpiperazine, a psychoactive molecule which shows a significant affinity for various serotonin receptors, induces a decrease of the size of the meal that follows the drug administration and reduces the intake of carbohydrates, fat and protein in healthy subjects and, to a lesser extent, in bulimic subjects. On the other hand, the administration of LTrp cause a decrease of fat intake in healthy subjects.…”