An analog of ACTH/MSH (4-9), ORG-2766, reduces cerebral uptake of morphine

Neurotrophic ACTH4-9 analogue therapy normalizes electroencephalographic alterations in chronic experimental allergic encephalomyelitis

Chronic experimental allergic encephalomyelitis (CEAE) is an established experimental model for multiple sclerosis (MS). The demyelinating lesions in the white matter of the central nervous system observed in CEAE and in MS are accompanied by various neurophysiological alterations. Among the best defined electrophysiological abnormalities are the changes in event-related potentials, in particular evoked potentials involving the spinal cord, i.e. motor and sensory evoked potentials. Less familiar are the changes observed in the electroencephalogram of CEAE-affected animals, which are also encountered in the human equivalent, MS. In the present experiment we evaluated the therapeutic value of a neurotrophic peptide treatment [H-Met(O2)-Glu-His-Phe-D-Lys-Phe-OH, an ACTH4-9 analogue] and its effect on the delayed flash visual evoked potentials (VEP) and power spectra of the electroencephalogram, during a 17-week follow-up of CEAE. CEAE animals treated with the neurotrophic peptide were protected against the development of neurological symptoms during the course of the demyelinating syndrome. VEPs of animals suffering from CEAE showed a delay of the latencies of the late components which was significantly counteracted by peptide treatment. The peak-to-peak amplitude of the VEP afterdischarge recorded from CEAE animals was significantly increased during the course of CEAE and correlated closely with the progression of the myelinopathy. Furthermore, CEAE animals showed an increase of electroencephalogram (EEG) beta activity of up to 500% as compared with the age-matched control group. This increase in beta power mainly consisted of a prevailing 20-21 Hz peak, a frequency that normally is not dominant in control EEG recordings of the rat during passive wakefulness. All these electrophysiological phenomena were absent in ACTH4-9 analogue-treated animals. The present findings underscore the potential importance of a neurotrophic peptide treatment in the pharmacotherapy of central demyelinating syndromes, and possibly of MS.

Use of adrenocorticotrophic hormone analog to minimize brain injury

STUDY OBJECTIVES

To investigate the effects of a vasoactive analog of adrenocorticotrophic hormone (GMM2) on time-dependent disturbances in regional cerebral blood flow, permeability-capillary surface area products, and intracranial pressure in a rat model of moderate concussion/brain injury.

SETTING AND DESIGN

Regional permeability-capillary surface area products and cerebral blood flow were measured at two hours after trauma. Intracranial pressure was monitored for 120 hours after trauma.

SUBJECTS

Male Wistar rats (330 to 430 g) (regional cerebral blood flow studies, n = 35; permeability-capillary surface area product studies, n = 36; intracranial pressure studies, n = 32).

INTERVENTIONS

Post-traumatic subcutaneous administration of nanomolar concentrations of GMM2 (31 nmol per rat).

MEASUREMENTS AND MAIN RESULTS

Untreated trauma acutely increased average brain permeability-capillary surface area products for sucrose and decreased average brain cerebral blood flow. Moreover, it produced marked and prolonged increases in intracranial pressure. Post-traumatic subcutaneous administration of nanomolar concentrations of GMM2 effectively reduced the early hypoperfusion, blood-brain barrier leakiness, and pathologic elevation of intracranial pressure.

CONCLUSION

Post-traumatic administration of GMM2, in nanomolar amounts, can prevent or reverse significantly the serious cerebrovascular sequelae of moderate head injury in this animal model. In view of its potency, low toxicity, and other neuroprotective properties, in both rats and human beings, these data suggest that GMM2 may have considerable clinical benefits in the treatment of central nervous system trauma.

An ACTH analog minimizes cerebrovascular damage in an animal model of moderate brain injury

An ACTH1-14-related analog (GMM2) was tested for efficacy in reducing the cerebrovascular pathology that follows moderate, closed-head injury in our rat model. Posttraumatic subcutaneous administration of nanomolar amounts of GMM2 significantly minimized both the hypoperfusion and the increased blood-brain permeability observed 2 h following a concussion. Posttraumatic administration of the peptide also reduced the elevated brain water content observed at 24 and 48 h postinjury to nonsignificant levels. These findings complement previously described observations that GMM2 treatment prevents dangerous elevations of ICP (> 25 mm Hg) at 24 to 72 h in this model of head injury. In view of the potency and low toxicity of GMM2 these observation suggest that the peptide may have considerable clinical application in interrupting pathologic sequelae of traumatic brain injury.

Central nervous system effects of peptides, 1980-1985: a cross-listing of peptides and their central actions from the first six years of the journal Peptides

A tabular synopsis is presented for articles concerned with the effects of peptides on the central nervous system that appeared in the journal Peptides from 1980-1985. A table arranged alphabetically by peptide and one arranged by effects, both listing routes of injection, species, direction of change, and qualifying notes, provides easy cross-referencing of peptides and their effects. Over 80 peptides and over 135 effects are listed. The list of peptides includes, but is not limited to: ACTH, angiotensin, bombesin, bradykinin, calcitonin, casomorphin, CCK, ceruletide, CGRP, CRF, dermorphin, DSIP, dynorphin, endorphins, enkephalins, GRF, gastrin, LHRH, litorin, metkephamid, MIF-l, motilin, MSH, NPY, NT, oxytocin, ranatensin, sauvagine, substances P and K, somatostatin, TRH, VIP, vasopressin, and vasotocin. The list of effects includes, but is not limited to: aggression, alcohol, analgesia, attention, avoidance, behavior, cardiovascular regulation, catalepsy, conditioned behavior, convulsions, dopamine binding and metabolism, discrimination, drinking, EEG, exploration, feeding, fever, gastric secretion, GI motility, grooming, learning, locomotor behavior, mating, memory, neuronal activity, open field, operant behavior, rearing, respiration, satiety, scratching, seizure, sleep, stereotypy, temperature, thermoregulation and tolerance.

Neuropeptides and social behavior of rats tested in dyadic encounters

The effects of various neuropeptides on social behavior was studied in a test procedure in which 7-day isolated animals were tested together with non-isolated partners in dyadic encounters. The short-term isolation procedure increased the frequency and duration of social activities of the rats, but hardly affected non-social explorative behaviors of the animals. Systemic injection of certain neuropeptides, i.c. prolyl-leucyl-glycinamide (PLG), thyrotropin releasing hormone (TRH) and the ACTH 4-9 analog ORG 2766, reversed the isolation-induced increase in social activity, similarly as previously observed with antidepressant drugs. Subcutaneous treatment with beta-endorphin, alpha-endorphin and des-Tyr-gamma-endorphin increased social interactions in 7-day isolated animals. beta-Endorphin enhanced social behavior of non-isolated rats as well, whereas gamma-MSH decreased the social interactions of these animals. Both peptides affected especially social contact behavior. The potent action of beta-endorphin suggests that this peptide and opioid systems may play a physiological role in social behavior. It is proposed that a possible functional antagonism between ACTH-like peptides, especially gamma-MSH, and beta-endorphin may operate in social behavior. The action of the peptides may be rather specific for social behavior, since none of the neuropeptides affected non-social explorative behaviors of the rats during the social interaction test.

Reduction of amygdaloid kindled seizures by an analog of ACTH/MSH

A behaviorally potent analog of ACTH/MSH(4-9), ORG-2766, markedly reduces both physiologic and behavioral components of convulsive seizures in an animal model of epilepsy--the amygdaloid kindled rat. We believe that such non-endocrine analogs of ACTH/MSH fragments may be clinically useful anticonvulsants, particularly in chronic applications, provided that their permeation of the blood-brain barrier can be improved.