Publikationsdatenbank

Evidence for functional involvement of TRPA1 and TRPV3 in ion transport across the colon of pigs (2019)

Art

Poster

Autoren

Manneck, D (WE 2)

Schrapers, Katharina T (WE 2)

Braun, H.S. (WE 2)

Stumpff, F (WE 2)

Kongress

98th meeting of the German Physiological Society

Ulm, 30.09. – 02.10.2019

Quelle

Acta physiologica : official journal of the Federation of European Physiological Societies

Bandzählung: 227

Heftzählung: S719

Seiten: 130 – 131

ISSN: 1748-1716

Sprache

Englisch

Verweise

URL (Volltext): https://www.eventclass.org/contxt_dpg2019/online-program/session?s=A+09

DOI: 10.1111/apha.13384

Kontakt

Institut für Veterinär-Physiologie

Oertzenweg 19 b
14163 Berlin
+49 30 838 62600
physiologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Previous investigations suggest that TRP channels play an important role in the transport of cations across the rumen, but data on the colon are rudimentary.

To monitor effects of the TRPV agonists thymol and cinnamaldehyde on the the short-circuit current (Isc) and conductance (Gt) across porcine colonic epithelia, tissues were placed in Ussing chambers (Ringer with 95% O2/5% CO2). Using qPCR, the expression levels of TRPV4, TRPV3 and TRPA1 in the stomach (fundus, cardia), duodenum, jejunum, ileum, caecum and colon of pigs were investigated. Additionally, intestinal sections were stained for TRPV3 and TRPV4 using immunohistochemistry (IHC). The patch clamp method was used to investigate overexpressing cells.

Mean Isc was 10.21 ± 1.48 µA·cm-2 and mean Gt 20.5 ± 0.62 µA·cm-2. Addition of 1 mmol·l-1 cinnamaldehyde, increased Isc and Gt by ΔIcinn = 19.52 ± 1.89 µA·cm-2 and ΔGcinn = 4.61 ± 0.29 mS·cm-2 (both p < 0.001). Neuronal involvement was excluded since the addition of lidocaine (1 mmol·l-1) did not block this response (p > 0.7). A low chloride solution (9.8 mmol·l-1, both sides) or 1 mmol·l-1 bumetanide had no significant effect on ΔIcinn (p > 0.1), while effects of 0.01 mmol·l-1 indometacin or 0.5 mmol·l-1 NPPB were only partial (62% and 47%, p < 0.001). The replacement of Na+ by NMDG+ significantly reduced ΔIcinn and ΔGcinn (by 86% and 79%, both p < 0.001). 1 mmol·l-1 of the ENaC blocker amiloride showed no effect, whereas 1 mmol·l-1 quinidine reduced ΔGcinn (p < 0.001). In Ca+ - free EGTA Ringer, ΔGcinn was increased (p < 0.001). Effects of thymol were more variable. Expression of mRNA for TRPV4 was highest in fundus and cardia, TRPA1 highest in colon, whereas TRPV3 could only be detected in colon and caecum, although immunofluorescence for TRPV3 and TRPV4 was detectable in all tissues. Patch clamp measurements showed a significant effect of thymol on cells overexpressing hTRPV3. Conversely, cinnamaldehyde had no effects on cells overexpressing either TRPV3 or TRPV4, supporting selective action on TRPA1 as previously reported.

In conjunction with qPCR data and IHC staining, functional data support a role for TRPA1 and TRPV3 in the transport of cations across the colon. These channels may thus play a role in mediating the intestinal transport of nutrients such as Ca2+ or fermentation products such as NH4+. The additional activation of chloride channels in native colonic epithelia most likely represents a downstream event following the influx of Ca2+.