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MSH/ACTH 4-10 and aging effects on delayed response performance in rats.
International Journal of Neurology
|January 1, 1987
Summary
Melanocyte-stimulating hormone/adrenocorticotropic hormone (MSH/ACTH) 4-10 peptide affects memory performance in rats. Young rats show improved memory with low doses, while aged rats exhibit a linear response, potentially linked to acetylcholine levels.
Area of Science:
- Neuroscience
- Pharmacology
- Gerontology
Background:
- Delayed response performance (DRP) is crucial for cognitive function.
- Aging is associated with cognitive decline, potentially linked to neurochemical changes.
- MSH/ACTH 4-10 is a peptide hormone with known cognitive effects.
Purpose of the Study:
- To investigate the impact of MSH/ACTH 4-10 on DRP in young and aged rats.
- To explore the dose-response relationship of MSH/ACTH 4-10 across the lifespan.
- To examine the potential role of the cholinergic system in MSH/ACTH 4-10's effects on DRP.
Main Methods:
- Utilized the Hunter paradigm with a Honzik opaque door modification to assess DRP.
- Administered various doses of MSH/ACTH 4-10 or control to male Long-Evans rats at 3 and 30 months of age.
- Assessed DRP monthly from 10 to 30 months, with and without psychoactive agents.
Main Results:
- A low dose (95 ug/kg) of MSH/ACTH 4-10 enhanced visual stimulus retention in young rats; higher doses impaired DRP.
- MSH/ACTH 4-10 reversed anticholinergic-induced DRP impairments, suggesting cholinergic mediation.
- Aged rats (≥23 months) showed impaired DRP at longer delays; age-related DRP changes were not due to sensory or motor deficits.
Conclusions:
- MSH/ACTH 4-10's effect on DRP shifts from an inverted 'U' dose-response in young rats to a linear response in aged rats.
- Age-related decreases in acetylcholine may alter MSH/ACTH 4-10's dose-response profile.
- Findings suggest potential therapeutic applications for age-related cognitive decline and Alzheimer's disease.