Accili, Daniela

Amenta, Francesco

Cadoni, Angela

Gabrielli, Maria Gabriella

Ricci, Alberto

Tomassoni, Daniele

Traini, Enea

Firenze University Press: E-Journals

IJAE Vol. 115, n. 1/2 (Supplement), 2010
9
Microanatomical localization of dopamine receptor 
subtypes in the rat gastrointestinal vasculature
Francesco Amenta1, Daniela Accili2, Angela Cadoni3, Maria Gabriella Gabrielli2, Enea Traini1, Alberto 
Ricci3, Daniele Tomassoni1
1 Human Anatomy, School of Pharmacy and 2 School of Bioscience and Biotechnology, University of Camerino, Italy
3 Department of Experimental Medicine, University of Genoa, Italy
4 Department of Respiratoty and Cardiovascular Sciences, University of Rome “La Sapienza”, Italy
The expression of dopamine (DA) D1-D5 receptor subtypes and their relationships 
with sympathetic neuroeffector plexus were investigated in mesenteric artery branches 
and different sized arteries of rat gastrointestinal tract by immunochemical and immu-
nohistochemical techniques. 
Male Sprague-Dawley rats were fasted for 24 h, anaesthetized and killed. Mesen-
teric artery and its main branches, stomach, duodenum, jejunum, ileum and colon were 
removed. Part of samples were put in a 30% sucrose solution, frozen and cut serially 
using a microtome cryostat. Sections were processed for tyrosine-hydroxylase (TH) and 
DA receptor protein immunohistochemistry. The remaining samples were homogenized 
and processed for Western blot analysis of the same parameters investigated immuno-
histochemically. 
DA D1-like (D1-D5) receptors were located in smooth muscle of superior mesenteric 
artery, muscular and submucous coats and mucous arteries of stomach, duodenum, je-
junum, ileum and colon. The D1 receptor was apparently more expressed than the D5 
receptor. DA D2-like (D2, D3 and D4) receptor immunoreactivity was located in the ad-
ventitia and adventitia-media border of superior mesenteric artery branches, muscular 
and submucous coats and mucous arteries of stomach, duodenum, jejunum, ileum and 
colon. The intensity of D3 receptor immunostaining as well as of TH immunoreactivity 
was inversely proportional to the decrease of arterial diameter. An association between 
TH and DA D2-like receptor was found in double immune staining experiments. 
The above findings indicate that rat superior mesenteric artery, gastric, small and 
large intestine arteries express the different subtypes of DA receptors. Both D1 and D5 
receptors are postjunctional while the demonstration of the co-expression of the sympa-
thetic marker TH and DA D2-like receptor protein immunoreactivity, indicates the pre-
junctional localization of these receptors. The particular microanatomical localization of 
DA receptors in rat gastrointestinal circulation suggests that their stimulation or inhibi-
tion may cause different hemodynamic consequences on gastrointestinal circulation. 
Key words
Dopamine receptors, gastrointestinal vasculature, immuhistochemistry


Microanatomical localization of dopamine receptor subtypes in the rat gastrointestinal vasculature

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Microanatomical localization of dopamine receptor subtypes in the rat gastrointestinal vasculature

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