Functional and molecular evidence for β1-, β2- and β3-adrenoceptors in human colon

S. J. Roberts, M. Papaioannou, B. A. Evans, R. J. Summers

Research output: Contribution to journalArticleResearchpeer-review

Abstract

1. Relaxation of carbachol pre-contracted human colonic muscle to (-)-isoprenaline was examined in circular, longitudinal and taenia coli preparations to determine the β-adrenoceptor subtypes involved. β1-, β2- and β3-Adrenoceptor mRNAs were also measured in colonic muscle and mucosa. 2. (-)-Isoprenaline caused relaxation of longitudinal smooth muscle preparations with pEC50 = 7.39 ± 0.12, and this response was inhibited by both propranolol (0.1 μM, pK(B) 8.55 ± 0.12) and the selective β1-antagonist, CGP 20712A (0.1 μM, pK(B) 8.80 ± 0.20), while the selective β2-antagonist, ICI 118551 (0.1 μM) failed to inhibit isoprenaline relaxation consistently. 3. (-)-Isoprenaline caused relaxation of taenia coli with a pEC50 of 6.70 ± 0.17. Propranolol (0.1 μM), CGP 20712A (0.1 μM) and ICI 118551 (0.1 μM) inhibited the isoprenaline response with similar low affinities (pK(B) values 7.93, 7.71 and 7.54, respectively). Carbachol pre-contracted circular smooth muscle preparations failed to relax consistently to isoprenaline and these responses were not characterized. 4. β1- and β2-Adrenoceptor mRNAs were present in circular/longitudinal muscle samples and taenia coli samples, and lower levels were detected in mucosa. β3-mRNA was also present in both muscle preparations but was not detected in human colonic mucosa. 5. In summary, β1-adrenoceptors are the predominant subtype mediating isoprenaline-induced relaxation of the thin longitudinal smooth muscle of human colon, while β3-receptors do not appear to be involved in these responses. However, β3-adrenoceptors may play a role in relaxation of the taenia coli as conventional antagonist affinities are low. β3-Adrenoceptor mRNA was present in taenia coli and circular/longitudinal smooth muscle but absent from human colonic mucosa.

Original languageEnglish
Pages (from-to)1527-1535
Number of pages9
JournalBritish Journal of Pharmacology
Volume120
Issue number8
DOIs
Publication statusPublished - 1 Jan 1997
Externally publishedYes

Keywords

  • Human colon
  • Messenger RNA
  • Mucosa
  • Smooth muscle
  • β-adrenoceptors

Cite this

Roberts, S. J. ; Papaioannou, M. ; Evans, B. A. ; Summers, R. J. / Functional and molecular evidence for β1-, β2- and β3-adrenoceptors in human colon. In: British Journal of Pharmacology. 1997 ; Vol. 120, No. 8. pp. 1527-1535.
@article{a11100733a044956b6d57a9e11b6a25f,
title = "Functional and molecular evidence for β1-, β2- and β3-adrenoceptors in human colon",
abstract = "1. Relaxation of carbachol pre-contracted human colonic muscle to (-)-isoprenaline was examined in circular, longitudinal and taenia coli preparations to determine the β-adrenoceptor subtypes involved. β1-, β2- and β3-Adrenoceptor mRNAs were also measured in colonic muscle and mucosa. 2. (-)-Isoprenaline caused relaxation of longitudinal smooth muscle preparations with pEC50 = 7.39 ± 0.12, and this response was inhibited by both propranolol (0.1 μM, pK(B) 8.55 ± 0.12) and the selective β1-antagonist, CGP 20712A (0.1 μM, pK(B) 8.80 ± 0.20), while the selective β2-antagonist, ICI 118551 (0.1 μM) failed to inhibit isoprenaline relaxation consistently. 3. (-)-Isoprenaline caused relaxation of taenia coli with a pEC50 of 6.70 ± 0.17. Propranolol (0.1 μM), CGP 20712A (0.1 μM) and ICI 118551 (0.1 μM) inhibited the isoprenaline response with similar low affinities (pK(B) values 7.93, 7.71 and 7.54, respectively). Carbachol pre-contracted circular smooth muscle preparations failed to relax consistently to isoprenaline and these responses were not characterized. 4. β1- and β2-Adrenoceptor mRNAs were present in circular/longitudinal muscle samples and taenia coli samples, and lower levels were detected in mucosa. β3-mRNA was also present in both muscle preparations but was not detected in human colonic mucosa. 5. In summary, β1-adrenoceptors are the predominant subtype mediating isoprenaline-induced relaxation of the thin longitudinal smooth muscle of human colon, while β3-receptors do not appear to be involved in these responses. However, β3-adrenoceptors may play a role in relaxation of the taenia coli as conventional antagonist affinities are low. β3-Adrenoceptor mRNA was present in taenia coli and circular/longitudinal smooth muscle but absent from human colonic mucosa.",
keywords = "Human colon, Messenger RNA, Mucosa, Smooth muscle, β-adrenoceptors",
author = "Roberts, {S. J.} and M. Papaioannou and Evans, {B. A.} and Summers, {R. J.}",
year = "1997",
month = "1",
day = "1",
doi = "10.1038/sj.bjp.0701056",
language = "English",
volume = "120",
pages = "1527--1535",
journal = "British Journal of Pharmacology",
issn = "1476-5381",
publisher = "Wiley-Blackwell",
number = "8",

}

Functional and molecular evidence for β1-, β2- and β3-adrenoceptors in human colon. / Roberts, S. J.; Papaioannou, M.; Evans, B. A.; Summers, R. J.

In: British Journal of Pharmacology, Vol. 120, No. 8, 01.01.1997, p. 1527-1535.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Functional and molecular evidence for β1-, β2- and β3-adrenoceptors in human colon

AU - Roberts, S. J.

AU - Papaioannou, M.

AU - Evans, B. A.

AU - Summers, R. J.

PY - 1997/1/1

Y1 - 1997/1/1

N2 - 1. Relaxation of carbachol pre-contracted human colonic muscle to (-)-isoprenaline was examined in circular, longitudinal and taenia coli preparations to determine the β-adrenoceptor subtypes involved. β1-, β2- and β3-Adrenoceptor mRNAs were also measured in colonic muscle and mucosa. 2. (-)-Isoprenaline caused relaxation of longitudinal smooth muscle preparations with pEC50 = 7.39 ± 0.12, and this response was inhibited by both propranolol (0.1 μM, pK(B) 8.55 ± 0.12) and the selective β1-antagonist, CGP 20712A (0.1 μM, pK(B) 8.80 ± 0.20), while the selective β2-antagonist, ICI 118551 (0.1 μM) failed to inhibit isoprenaline relaxation consistently. 3. (-)-Isoprenaline caused relaxation of taenia coli with a pEC50 of 6.70 ± 0.17. Propranolol (0.1 μM), CGP 20712A (0.1 μM) and ICI 118551 (0.1 μM) inhibited the isoprenaline response with similar low affinities (pK(B) values 7.93, 7.71 and 7.54, respectively). Carbachol pre-contracted circular smooth muscle preparations failed to relax consistently to isoprenaline and these responses were not characterized. 4. β1- and β2-Adrenoceptor mRNAs were present in circular/longitudinal muscle samples and taenia coli samples, and lower levels were detected in mucosa. β3-mRNA was also present in both muscle preparations but was not detected in human colonic mucosa. 5. In summary, β1-adrenoceptors are the predominant subtype mediating isoprenaline-induced relaxation of the thin longitudinal smooth muscle of human colon, while β3-receptors do not appear to be involved in these responses. However, β3-adrenoceptors may play a role in relaxation of the taenia coli as conventional antagonist affinities are low. β3-Adrenoceptor mRNA was present in taenia coli and circular/longitudinal smooth muscle but absent from human colonic mucosa.

AB - 1. Relaxation of carbachol pre-contracted human colonic muscle to (-)-isoprenaline was examined in circular, longitudinal and taenia coli preparations to determine the β-adrenoceptor subtypes involved. β1-, β2- and β3-Adrenoceptor mRNAs were also measured in colonic muscle and mucosa. 2. (-)-Isoprenaline caused relaxation of longitudinal smooth muscle preparations with pEC50 = 7.39 ± 0.12, and this response was inhibited by both propranolol (0.1 μM, pK(B) 8.55 ± 0.12) and the selective β1-antagonist, CGP 20712A (0.1 μM, pK(B) 8.80 ± 0.20), while the selective β2-antagonist, ICI 118551 (0.1 μM) failed to inhibit isoprenaline relaxation consistently. 3. (-)-Isoprenaline caused relaxation of taenia coli with a pEC50 of 6.70 ± 0.17. Propranolol (0.1 μM), CGP 20712A (0.1 μM) and ICI 118551 (0.1 μM) inhibited the isoprenaline response with similar low affinities (pK(B) values 7.93, 7.71 and 7.54, respectively). Carbachol pre-contracted circular smooth muscle preparations failed to relax consistently to isoprenaline and these responses were not characterized. 4. β1- and β2-Adrenoceptor mRNAs were present in circular/longitudinal muscle samples and taenia coli samples, and lower levels were detected in mucosa. β3-mRNA was also present in both muscle preparations but was not detected in human colonic mucosa. 5. In summary, β1-adrenoceptors are the predominant subtype mediating isoprenaline-induced relaxation of the thin longitudinal smooth muscle of human colon, while β3-receptors do not appear to be involved in these responses. However, β3-adrenoceptors may play a role in relaxation of the taenia coli as conventional antagonist affinities are low. β3-Adrenoceptor mRNA was present in taenia coli and circular/longitudinal smooth muscle but absent from human colonic mucosa.

KW - Human colon

KW - Messenger RNA

KW - Mucosa

KW - Smooth muscle

KW - β-adrenoceptors

UR - http://www.scopus.com/inward/record.url?scp=0030936098&partnerID=8YFLogxK

U2 - 10.1038/sj.bjp.0701056

DO - 10.1038/sj.bjp.0701056

M3 - Article

VL - 120

SP - 1527

EP - 1535

JO - British Journal of Pharmacology

JF - British Journal of Pharmacology

SN - 1476-5381

IS - 8

ER -