Identification of a melanocortin-dependent anti-shock pathway: brain-to-immune system cholinergic communication

Identification of a melanocortin-dependent anti-shock pathway: brain-to-immune system cholinergic communicatio

Neuroprotection against ischemic stroke by early or delayed treatment with MC4 receptor-stimulating melanocortins

Here we investigated whether melanocortin peptides, which have protective effects in severe hypoxic conditions, are able to produce neuroprotection in ischemic stroke. Our findings suggest that melanocortins that are agonist at the MC4 receptors may represent a class of drugs with a broad therapeutic window for a new approach to neuroprotection in ischemic strok

Broad therapeutic treatment window of [Nle(4), D-Phe(7)]alpha-melanocyte-stimulating hormone for long-lasting protection against ischemic stroke, in Mongolian gerbils

Melanocortin peptides have been shown to produce neuroprotection in experimental ischemic stroke. The aim of the present investigation was to identify the therapeutic treatment window of melanocortins, and to determine whether these neuropeptides chronically protect against damage consequent to brain ischemia. A 10-min period of global cerebral ischemia in gerbils, induced by occluding both common carotid arteries, caused impairment in spatial learning and memory (Morris test: four sessions from 4 to 67 days after the ischemic episode), associated with neuronal death in the hippocampus. Treatment with a nanomolar dose (340 mu g/kg i.p., every 12 h for 11 days) of the melanocortin analog [Nle(4), D-Phe(7)]alpha-metanocyte-stimulating hormone (NDP-alpha-MSH), starting 3-18 h after the ischemic episode, reduced hippocampal damage with improvement in subsequent functional recovery. The protective effect was long-lasting (67 days, at least) with all schedules of NDP-alpha-MSH treatment; however, in the latest treated (18 h) gerbils, some spatial memory deficits were detected. Pharmacological blockade of melanocortin MC4 receptors prevented the protective effects of NDP-alpha-MSH. Our findings indicate that, in conditions of brain ischemia, melanocortins can provide strong and longlasting protection with a broad therapeutic treatment window, and with involvement of melanocortin MC4 receptors, 18 h being the approximately time-limit for stroke late treatment to be effective

Both Early and Delayed Treatment with Melanocortin 4 Receptor-Stimulating Melanocortins Produces Neuroprotection in Cerebral Ischemia

Ischemic stroke is one of the main causes of death and disability. We investigated whether melanocortin peptides, which have protective effects in severe hypoxic conditions, also produce neuroprotection in a gerbil model of ischemic stroke. A 10-min period of global cerebral ischemia, induced by occluding both common carotid arteries, caused impairment in spatial learning and memory that was associated with activation of inflammatory and apoptotic pathways, including severe DNA damage and delayed neuronal death, in the hippocampus. Treatment with nanomolar doses of the melanocortin analog [Nle4, D-Phe7] {alpha}-MSH [which activates the melanocortin receptor subtypes (MC) mainly expressed in central nervous system, namely MC3 and MC4] modulated the inflammatory and apoptotic cascades and reduced hippocampus injuries even when delayed up to 9 h after ischemia, with consequent dose-dependent improvement in subsequent functional recovery. The selective MC3 receptor agonist {gamma}2-MSH had no protective effects. Pharmacological blockade of MC4 receptors prevented the neuroprotective effects of [Nle4, D-Phe7] {alpha}-MSH and worsened some ischemia outcomes. Together, our findings suggest that MC4 receptor-stimulating melanocortins might provide potential to develop a class of drugs with a broad treatment window for a novel approach to neuroprotection in ischemic stroke

Activation of an efferent cholinergic pathway produces strong protection against myocardial ischemia/reperfusion injury in rats

Objective: A vagus nerve-mediated, brain cholinergic protective mechanism activated by melanocortin peptides is operative in conditions of circulatory shock; moreover, there is anatomical evidence of dual vagal-cardiac efferent pathways in rats, which could play different roles in controlling heart function. Therefore, we investigated the role and functional mechanism of such vagal efferent pathway(s) in an experimental model of ischemic heart disease. Design: Randomized experimental study. Setting: Research laboratory. Subjects: Adult Wistar rats of either sex. Interventions: After bilateral cervical vagotomy (with or without pretreatment with atropine), efferent vagal fibers were electrically stimulated in rats subjected to coronary artery occlusion (5 mins) followed by reperfusion (5 mins). Other rats (intact, vagotomized, or pretreated with atropine) were treated with nanomolar doses of melanocortin peptides. Measurements and Main Results: Electrical stimulation of efferent vagal fibers (5 V, 2 msecs,1-9 Hz, for the whole period of ischemia/reperfusion) strongly reduced the high incidence of severe arrhythmias and lethality, reduced the increase in free radical blood levels and left-ventricle histologic alterations, and augmented the extracellular signal-regulated kinase activation. Treatment with the melanocortin peptides adrenocorticotropin and gamma(2)-melanocyte-stimulating hormone (162 nmol/kg intravenously or 16.2 nmol/kg intracerebroventricularly, during coronary occlusion) produced the same protective effects of electrical stimulation and with the same muscarinic acetylcholine receptor-dependent mechanism, seemingly through brain activation (mediated by melanocortin MC3 receptors, as previously described) of such efferent vagal pathway. Conclusions: The present results give evidence for the identification of a protective, melanocortin-activated, efferent vagal cholinergic pathway, operative in conditions of myocardial ischemia/reperfusion. These data suggest that melanocortins and pertinent compounds able to activate such a pathway could provide the potential for development of a new class of drugs for a novel approach to management of ischemic heart disease

Both early and delayed treatment with melanocortin 4 receptor-stimulating melanocortins produces neuroprotection in cerebral ischemia

Ischemic stroke is one of the main causes of death and disability. We investigated whether melanocortin peptides, which have protective effects in severe hypoxic conditions, also produce neuroprotection in a gerbil model of ischemic stroke. A 10-min period of global cerebral ischemia, induced by occluding both common carotid arteries, caused impairment in spatial learning and memory that was associated with activation of inflammatory and apoptotic pathways, including severe DNA damage and delayed neuronal death, in the hippocampus. Treatment with nanomolar doses of the melanocortin analog [Nle(4), D-Phe(7)] alpha-MSH [which activates the melanocortin receptor subtypes ( MC) mainly expressed in central nervous system, namely MC3 and MC4] modulated the inflammatory and apoptotic cascades and reduced hippocampus injuries even when delayed up to 9 h after ischemia, with consequent dose-dependent improvement in subsequent functional recovery. The selective MC3 receptor agonist gamma(2)-MSH had no protective effects. Pharmacological blockade of MC4 receptors prevented the neuroprotective effects of [Nle(4), D-Phe(7)] alpha-MSH and worsened some ischemia outcomes. Together, our findings suggest that MC4 receptor-stimulating melanocortins might provide potential to develop a class of drugs with a broad treatment window for a novel approach to neuroprotection in ischemic stroke