DISTRIBUTION OF ACETYLCHOLINESTERASE AND CHOLINEACETYL-TRANSFERASE ACTIVITIES IN CORONARY VESSELS OF YOUNGER AND OLDER ADULTS

Background: The cholinergic nerve fibers of coronary arteries, capillaries and veins were studied in younger and older humans by staining of acetylcholinesterase and choline- acetyltransferase activities on autopsy samples of coronary vessels with the aim of inves- tigating age-related changes. Methods: Samples of human coronary vessels were harvested and exposed to the enzy- matic staining for acetylcholinesterase, immunohistochemical staining for cholineacetyl- transferase and quantitative analysis of images. Morphometric values were subjected to statistical analysis of data. Results: Our results demonstrated that both acetylcholinesterase and cholineacetyl- transferase are localized in the coronary vessels of younger and older humans. Staining of these two enzymes showed specific age-related changes. Structures resembling cholinergic nerve fibers were located in coronary vessels, in the extra-parenchymal (large caliber) and intraparenchymal (small caliber) branches (arteries and veins), organized in a plexus. Cor- onary arterioles of large caliber (diameter > 150 mm) were found to have many cholinergic nerve fibers. The quantitative analysis of images and the statistical analysis of the data dem- onstrated that the cholinergic neurotransmitters of coronary vessels (especially the extra- parenchymal branches of coronary arteries) strongly decrease with age. Conclusions: The age-related changes of cholinergic nerve supply of the human coro- nary vessels may play a role in the control of coronary circulation. Further studies are needed in order to draw definite conclusions concerning the nervous control of coronary circulation under normal and/or pathological conditions

Age related changes of monoaminoxidases in rat cerebellar cortex.

Age-related changes of the monoaminoxidases, evaluated by enzymatic staining, quantitative analysis of images, biochemical assay and statistical analysis of data were studied in cerebellar cortex of young (3-month-old) and aged (26- month-old) male Sprague-Dawley rats. The enzymatic staining shows the presence of monoamino-oxidases within the molecular and granular layers as well as within the Purkinje neurons of the cerebellum of young and aged animals. In molecular layer, and in Purkinje neurons the levels of monoaminooxidases were strongly increased in old rats. The granular layer showed, on the contrary, an age-dependent loss of enzymatic staining. These morphological findings were confirmed by biochemical results. The possibility that age-related changes in monoaminooxidase levels may be due to impaired energy production mechanisms and/or represent the consequence of reduced energetic needs is discussed

Dopamine nerve fibres and related receptors in bronchus-associated lymphoid tissue (BALT).

Age-related changes of the dopamine nerve fibres of bronchus associated lymphoid tissue (BALT) were investigated in male Wistar rats of 3 months (young), and 24 months (old/aged). Dopamine histofluorescence techniques have been used, associated with image analysis for the detection of dopamine nerve fibres. In young rats, white, fluorescent nerve fibres supply BALT. This tissue is innervated by a delicate network of nerve fibres rich in varicosities. In old rats these fluorescent nerve fibres are strongly reduced. Moreover, dopamine D1a and D1b receptors were stained using fluorescent monoclonal antibodies. The BALT of young rats possesses a higher number of D1a and D1b receptors, while, in the old rats, these receptors are strongly reduced. The possible significance of reduced dopamine neurotransmission in BALT of aged rats is discussed