Specific binding of the dopamine receptor ligand 3H-spiroperidol to cell membranes prepared from the caudate nuclei and putamens of 29 rhesus monkeys (M. mulatta), ranging in age from 2 to 22 years, was investigated. Receptor concentration (Bmax) decreased in the caudate nucleus and putamen with age at mean rates of 2.1 and 1.7% per year, respectively, whereas binding affinity (Kd) did not change significantly with age. The rate of decline in Bmax appeared to be more rapid before adulthood and in old age than during young adulthood and middle age. These data are compared with the results from similar studies of other animal species including human, rabbit, rat, and mouse. The rate of decline in striatal dopamine receptors is closely related to the rate of aging and maximal life span of the species. It may reflect both maturational and senescent processes modifying the behavior of animals as they age.

Aging↗

PubMedDate not supplied

Punch sampling technique for quantitative identification of tritiated D-amphetamine.

A punch sampling, tissue solubilization, and scintillation counting technique has been devised for the quantitative identification of tritiated d-amphetamine in monkey brain tissue. The method is superior to autoradiography in identifying this water soluble radiochemical, and is easier and more anatomically precise than radiochemical assay of brain homogenates. This rapid and simple technique allows one to survey the whole brain by sampling unit volumes of individual structures verified by light microscopy. The procedure consists of six steps which may be spaced as the laboratory schedule permits: obtaining tissue blocks, preparation for sectioning, punch sampling and sectioning, preparing samples for scintillation counting, histological verification of sample sites, and analysis of scintillation count data. The technique has been successfully used to demonstrate a gradient of radioactivity following experimental intraventricular injections of 3H amphetamine.

Animals↗

PubMedDate not supplied

Achondroplasia in Holstein-Friesian cattle.

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Achondroplasia↗