Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 1987 Apr;35(4):334-45.
doi: 10.1111/j.1532-5415.1987.tb04641.x.

Dopamine and serotonin systems in human and rodent brain: effects of age and neurodegenerative disease

D G Morgan, P C May, C E Finch
Review

Dopamine and serotonin systems in human and rodent brain: effects of age and neurodegenerative disease

D G Morgan et al. J Am Geriatr Soc. 1987 Apr.

Abstract

The nonpathological age-related changes in the dopamine- and serotonin-containing neurotransmitter systems in human and rodent brain are reviewed. The dopamine system exhibits age-related declines both presynaptically and postsynaptically. Presynaptically, both the levels of dopamine and the number of midbrain dopamine-containing neurons decline by up to 50% at advanced ages in the absence of neurological disease. Postsynaptically, the density of D-2 dopamine receptors decreases by 40%, while D-1 dopamine receptors either increase (man) or remain stable (rodents). Additional reductions of dopamine levels and D-2 receptors have been reported in Alzheimer's disease (AD), but these changes are relatively small, and not consistently observed. The levels of serotonin appear stable during normal aging, and presynaptic markers such as (3H)imipramine binding may actually increase. In human brain, the two major classes of serotonin receptor (S-1 and S-2) decrease by 30 to 50% over the lifespan. In AD, both presynaptic and postsynaptic markers of the serotonin system are reduced, including a loss of the serotonin-containing raphe neurons. The additional loss of serotonin receptors in AD approaches 80% when compared with young normals. A hypothesis is presented to explain the typically young age at onset of schizophrenia (usually before 30 years of age) and the older age at onset of parkinsonism (rarely before 50 years of age) within the context of normal age-related declines in the dopamine system occurring in the absence of neurological disorders. The possibility that chronic cocaine abuse might accelerate the development of parkinsonism is discussed.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

Publication types

LinkOut - more resources