Distribution of catecholaminergic neurotransmitters and related receptors in human bronchus-associated lymphoid tissue.
BACKGROUND
The functions of the bronchus-associated lymphoid tissue (BALT) are under the control of the autonomic nervous system (sympathetic and parasympathetic nerve fibers).


OBJECTIVE
The relationships between the adrenergic nerve fibers and beta-adrenergic receptors were studied in the human BALT with the aim to demonstrate a probable neuromodulation.


METHODS
Morphological observations (staining with hematoxylin-eosin and scanning electron microscopy images) were carried out on samples of human BALT harvested during autopsies. Moreover, histochemical staining for norepinephrine (adrenaline = adrenergic nerve fibers) as well as for other catecholamines was performed. Finally, beta-adrenergic receptors were stained by means of a beta-blocking, radiolabeled drug (pindolol 125I). All our data were submitted to morphometric analysis (quantitative analysis of images and statistical analysis of data).


RESULTS
Our results provide direct evidence of the presence and distribution of catecholaminergic nerve fibers and related beta-adrenergic receptors in BALT. beta-Adrenergic receptors are present above all in the most richly innervated part of the BALT, and are, therefore, in close relationship with their related adrenergic nerve fibers.


CONCLUSIONS
Studies on the distribution of adrenergic neurotransmitters and related beta-adrenergic receptors in the human BALT are the first step for the demonstration of a probable neuromodulation of BALT.
Cavallotti
Carlo
C
Department of Cardiovascular and Respiratory Sciences, University of Rome La Sapienza, Rome, Italy. cavallotti@uniroma1.it
Bruzzone
Paolo
P
Tonnarini
Gianfranco
G
Cavallotti
Daniela
D
D000320:Adrenergic Fibers / Q000378:metabolism*; D001345:Autoradiography; D006801:Humans; D007150:Immunohistochemistry; D008221:Lymphoid Tissue / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011943:Receptors, Adrenergic, beta; D009638:Norepinephrine