Activation of angiotensin <scp>II</scp> type 1 receptors and contractile activity in human sigmoid colon <i>in vitro</i>

Mastropaolo, Mariangela; Zizzo, Maria Grazia; Auteri, Michelangelo; Caldara, Gaetano Felice; Liotta, Rosa; Mulè, Flavia; Serio, Rosa

doi:10.1111/apha.12538

Cited by 15 publications

(12 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The methods used in this study have been previously described . Briefly, the colonic segments were opened along the border of a taenia, carefully cleaned to prevent soiling of the muscle layers with fecal content, and pinned to the surface of a dissecting dish filled with oxygenated Krebs solution.…”

Section: Methodsmentioning

confidence: 99%

Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon

Zizzo

Bellanca

Amato

et al. 2020

Neurogastroenterology Motil

View full text Add to dashboard Cite

The idea of a dopaminergic enteric transmission, independent of the sympathoadrenal system, has been proposed different years ago due to the observations that neurons, expressing both the dopamine (DA)-synthesizing enzyme and the dopamine transporter, but not the norepinephrine-synthesizing enzyme, were present within the enteric nervous system (ENS) in both animal models and humans. 1,2 DA seems to be implicated in several functions in GI tract, 3 activating specific receptors belonging to the G protein-coupled receptor family categorized in two main families: D1-like receptor (D1 and D5 receptors) and D2-like receptor(D2, D3, and D4 receptors), present from the stomach through the distal colon in different animal species. 2 Abstract Background: Because dopamine (DA) has gained increasing evidence as modulator of gut motility, we aimed to characterize dopaminergic response in human colon, evaluating function and distribution of dopamine receptors in circular vs longitudinal muscle strips. Methods: Mechanical responses to DA and dopaminergic agonists on slow phasic contractions and on basal tone were examined in vitro as changes in isometric tension. RT-PCR was used to reveal the distribution of dopaminergic receptors. Key Results: In spontaneous active circular muscle, DA induced an increase in the amplitude of slow phasic contractions and of the basal tone, via activation of D1-like receptors. DA contractile responses were insensitive to neural blockers or to atropine and inhibited by phospholipase C (PLC) pathway inhibitors. In precontracted circular muscle strips, DA, at the higher concentrations tested, caused a relaxant response via activation of D2-like receptors. In the longitudinal muscle, DA caused only muscular relaxation due to activation of D2-like receptors. DA relaxant responses were insensitive to neural blockers or to nitric oxide synthase inhibitor and reduced by a wide-spectrum K + channel blockers. Transcripts encoding for all the dopaminergic receptor subtypes was observed in both circular and longitudinal preparations. Conclusions and inferences: Dopamine is able to modulate contractile activity of the human colon. In the circular muscle layer, DA induces mainly muscular contraction activating non-neural D1-like receptors, coupled to PLC/IP3 pathway. In the longitudinal muscle layer, DA induces muscular relaxation acting on non-neural D2-like receptors leading to the increase in K + conductance. K E Y W O R D S circular and longitudinal muscle, dopamine, dopaminergic receptors human colon, intestinal motility

show abstract

Section: Methodsmentioning

confidence: 99%

Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon

Zizzo

Bellanca

Amato

et al. 2020

Neurogastroenterology Motil

View full text Add to dashboard Cite

show abstract

“…Each preparation was tested with a single antagonist, unless otherwise stated. Concentrations of the drugs used were determined from previous experiments and from literature.…”

Section: Methodsmentioning

confidence: 99%

Angiotensin II type II receptors and colonic dysmotility in 2,4‐dinitrofluorobenzenesulfonic acid‐induced colitis in rats

Zizzo

Auteri

Amato

et al. 2017

Neurogastroenterology Motil

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nevertheless, these reports on the specificity of AGTR1 markers can still be challenged with the accurate findings obtained from the knockdown or knockout animals used in such studies (Ito et al, 1995), in addition to the use of immunolabeling controls for each patch of the primary antibody used. Until such controversy is definitively solved, immunohistochemical studies will remain a complement to other methods of AGTR1 detection (Huang et al, 2016, Ishiguro et al, 2015, Mastropaolo et al, 2015, Zawada et al, 2015, Premer et al, 2013 and support the findings which hypothesize that the SMO is an overlooked CVO.…”

Section: Discussionmentioning

confidence: 76%

Expression of ZO1, vimentin, pan-cadherin and AGTR1 in tanycyte-like cells of the sulcus medianus organum

Al-Kaabi

Hussam

Al-Marsoummi

et al. 2018

Biochemical and Biophysical Research Communications

View full text Add to dashboard Cite

Tanycytes are a specialized ependymal lining of brain ventricles with exceptional features of having long basal processes and junctional complexes between cell bodies. These tanycytes are present at the regions of circumventricular organs (CVOs) which possess common morphological and functional features enabling them to be described as the brain windows where the barrier systems have special properties. Previous studies detailed seven of these CVOs but little information is available regarding another putative site at the rostral part of the median sulcus of the 4th ventricle, or the sulcus medianus organum (SMO). Here we performed a pilot immunohistochemical study to support earlier observations suggesting the SMO as a novel CVO. We labeled rat brain with ZO1, vimentin, pan-cadherin and angiotensin II type 1 receptors markers which showed a morphologically distinct population of cells at the region of the SMO similar to tanycytes present in the median eminence, a known CVO. These cells had basal processes reaching the deeply seated blood vessels while the caudal part of the median sulcus did not show similar long cellular extensions. We concluded that tanycyte-like cells are present in the SMO in a pattern resembling that of other CVOs where the strategic location of the SMO is probably for signal integration between brainstem nuclei and the rostrally located neuronal centers.

show abstract

Activation of angiotensin II type 1 receptors and contractile activity in human sigmoid colon in vitro

Cited by 15 publications

References 42 publications

Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon

Opposite effects of dopamine on the mechanical activity of circular and longitudinal muscle of human colon

Angiotensin II type II receptors and colonic dysmotility in 2,4‐dinitrofluorobenzenesulfonic acid‐induced colitis in rats

Expression of ZO1, vimentin, pan-cadherin and AGTR1 in tanycyte-like cells of the sulcus medianus organum

Contact Info

Product

Resources

About