Cardiovascular effects of melanin-concentrating hormone

Messina, M; Overton, J. M.

doi:10.1016/j.regpep.2006.08.013

Cited by 30 publications

(27 citation statements)

References 28 publications

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“…This condition was not included in a previous investigation (22). In the first 2 h after the acute injection of the MCHR1 agonist, we observed a slight yet not significant decrease in the energy expenditure of pair-fed rats.…”

Section: Discussionmentioning

confidence: 55%

“…Oxygen consumption (V O2) and carbon dioxide production (V CO2) were measured every 14 min over ϳ3 h, (from the 29th to the 197th min after the injection). This 3-h duration was selected as previous results on core body temperature (43) and heart rate (22) have indicated that most of the MCH (or MCH agonist) effects on body metabolism happen within the first 3 h following administration of the peptide.…”

Section: Animalsmentioning

confidence: 99%

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Effects of intracerebroventricular and intra-accumbens melanin-concentrating hormone agonism on food intake and energy expenditure

Guesdon¹,

Paradis²,

Samson³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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Guesdon B, Paradis É , Samson P, Richard D. Effects of intracerebroventricular and intra-accumbens melanin-concentrating hormone agonism on food intake and energy expenditure. Am J Physiol Regul Integr Comp Physiol 296: R469 -R475, 2009. First published January 7, 2009 doi:10.1152/ajpregu.90556.2008.-The brain melanin-concentrating hormone (MCH) system represents an anabolic system involved in energy balance regulation through influences exerted on the homeostatic and nonhomeostatic controls of food intake and energy expenditure. The present study was designed to further delineate the effect of the MCH system on energy balance regulation by assessing the actions of the MCH receptor 1 (MCHR1) agonism on both food intake and energy expenditure after intracerebroventricular (third ventricle) and intra-nucleus-accumbens-shell (intraNAcSH) injections of a MCHR1 agonist. Total energy expenditure and substrate oxidation were assessed following injections in male Wistar rats using indirect calorimetry. Food intake was also measured. Pair-fed groups were added to evaluate changes in thermogenesis that would occur regardless of the meal size and its thermogenic response. Using such experimental conditions, we were able to demonstrate that acute MCH agonism in the brain, besides its orexigenic effect, induced a noticeable change in the utilization of the main metabolic fuels. In pair-fed animals, MCH significantly reduced lipid oxidation when it was injected in the third ventricle. Such an effect was not observed following the injection of MCH in the NAcSH, where MCH nonetheless strongly stimulated appetite. The present results further delineate the influence of MCH on energy expenditure and substrate oxidation while confirming the key role of the NAcSH in the effects of the MCH system on food intake. brain; feeding behavior; substrate oxidation; energy balance IN THE BRAIN, SEVERAL INTERCONNECTED neurons receiving inputs from peripheral and central signals exert complex controls on food intake and energy expenditure, which are the two inescapable determinants of energy balance (6,13,23,31). In recent years, a few groups of investigators have directed their attention to one of the regulatory determinants of energy balance, namely the melanin-concentrating hormone (MCH) system. MCH-containing neurons are concentrated within the lateral hypothalamus (LH) and the adjacent zona incerta from where they project to the rest of the brain (7), in a pattern that generally conforms to the distribution of the MCH receptor 1 (MCHR1, the functional MCH receptor in rats and mice) (17).Evidence that the MCH system is involved in body weight regulation has emerged from various sources (24, 29). Hypothalamic expression of MCH mRNA is upregulated during starvation in lean mice, as well as in genetically obese ob/ob mice (30), and MCH overexpression leads to obesity and to an increased susceptibility to high-fat feeding (19). In addition, acute or chronic intracerebroventricular administration of MCH or MCHR1 agonists stimulate feeding in r...

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Section: Discussionmentioning

confidence: 55%

Section: Animalsmentioning

confidence: 99%

Effects of intracerebroventricular and intra-accumbens melanin-concentrating hormone agonism on food intake and energy expenditure

Guesdon¹,

Paradis²,

Samson³

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…infusions of either MCH or an MCH-1 receptor antagonist had no effect on daily home-cage activity [12,17,[36][37][38]. It should be noted, however, that in three of these studies, chronic MCH treatment failed to increase food intake [12,36,37]. Clearly, additional studies are required to better understand the impact of acute versus chronic administration of MCH on food intake and locomotor energy expenditure.…”

Section: Discussionmentioning

confidence: 93%

The orexigenic effect of melanin-concentrating hormone (MCH) is influenced by sex and stage of the estrous cycle

Santollo

Eckel

2008

Physiology & Behavior

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Recently, it was shown that that the orexigenic effect of melanin concentrating hormone (MCH) is attenuated by estradiol treatment in ovariectomized (OVX) rats. This suggests that female rats may be less responsive than male rats to the behavioral effects of MCH. To investigate this hypothesis, the effects of lateral ventricular infusions of MCH on food intake, water intake, meal patterns, and running wheel activity were examined in male and female rats. To further characterize the impact of estradiol on MCH-induced food intake, female rats were OVX and tested with and without 17-β-estradiol benzoate (EB) replacement. In support of our hypothesis, food and water intakes following MCH treatment were greater in male rats, relative to female rats. Specifically, the orexigenic effect of MCH was maximal in male rats and minimal in EB-treated OVX rats. In both sexes, the orexigenic effect of MCH was mediated by a selective increase in meal size, which was attenuated in EB-treated OVX rats. MCH induced a short-term (2 h) decrease in wheel running that, unlike its effects on ingestive behavior, was similar in males and females. Thus, estradiol decreases some, but not all, of the behavioral effects of MCH. To examine the influence of endogenous estradiol, food intake was monitored following MCH treatment in ovarian-intact, cycling rats. As predicted by our findings in OVX rats, the orexigenic effect of MCH was attenuated in estrous rats, relative to diestrous rats. We conclude that the female rat's reduced sensitivity to the orexigenic effect of MCH may contribute to sex-and estrous cycle-related differences in food intake.

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“…Although an earlier report (Messina and Overton, 2007) indicated that MCH elicits decreases in BP and HR, the peptide was injected i.c.v. in that study.…”

Section: Discussionmentioning

confidence: 99%

“…For example, mice lacking MCH-1 receptor exhibit an increase in heart rate (Astrand et al, 2004) and i.c.v. administration of MCH elicits hypotension and bradycardia in rats (Messina and Overton, 2007).…”

Section: Introductionmentioning

confidence: 94%

Microinjections of melanin concentrating hormone into the nucleus tractus solitarius of the rat elicit depressor and bradycardic responses

et al. 2007

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The presence of melanin-concentrating hormone (MCH) containing processes, projecting from the lateral hypothalamus to the medial nucleus tractus solitarius (mNTS), has been reported in the rat. It was hypothesized that MCH acting within the mNTS may modulate the central regulation of cardiovascular function. This hypothesis was tested in urethane-anesthetized, artificially ventilated, adult male Wistar rats. Microinjections (100 nl) of MCH (0.25, 0.5, 0.75, and 1 mM) into the mNTS of anesthetized rats elicited decreases in mean arterial pressure (20.4 ± 1.6, 50.7 ± 3.3, 35.7 ± 2.8 and 30.0 ± 2.6 mmHg, respectively). The decreases in heart rate in response to these concentrations of MCH were 40.0 ± 8.7, 90.0 ± 13.0, 48.0 ± 7.3 and 48.0 ± 8.0 beats/min, respectively. Maximum cardiovascular responses were elicited by a 0.5 mM concentration of MCH. Cardiovascular responses to MCH were similar in unanesthetized mid-collicular decerebrate rats. Control microinjections of normal saline (100 nl) did not elicit any cardiovascular response. Ipsilateral or bilateral vagotomy significantly attenuated MCH-induced bradycardia. Prior microinjections of PMC-3881-PI (2 mM; MCH-1 receptor antagonist) into the mNTS blocked the cardiovascular responses to microinjections of MCH. Microinjection of MCH (0.5 mM) into the mNTS decreased efferent greater splanchnic nerve activity. Direct application of MCH (0.5 mM; 4 nl) to barosensitive NTS neurons increased their firing rate. These results indicate that: 1) MCH microinjections into the mNTS activate MCH-1 receptors and excite barosensitive NTS neurons, causing a decrease in efferent sympathetic activity and blood pressure, and 2) MCH-induced bradycardia is mediated via the activation of the vagus nerves.

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Cardiovascular effects of melanin-concentrating hormone

Cited by 30 publications

References 28 publications

Effects of intracerebroventricular and intra-accumbens melanin-concentrating hormone agonism on food intake and energy expenditure

Effects of intracerebroventricular and intra-accumbens melanin-concentrating hormone agonism on food intake and energy expenditure

The orexigenic effect of melanin-concentrating hormone (MCH) is influenced by sex and stage of the estrous cycle

Microinjections of melanin concentrating hormone into the nucleus tractus solitarius of the rat elicit depressor and bradycardic responses

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