Cytochalasin-B and phloretin depress contraction and relaxation of aortic smooth muscle

Peter E. Dresel; Leah Knickle

doi:10.1016/0014-2999(87)90514-0

Cytochalasin-B and phloretin depress contraction and relaxation of aortic smooth muscle

Peter E. Dresel, Leah Knickle

Medicine

Medicine

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

Cytochalasin-B (20 μM) and phloretin (100 μM) blocked by more than 80% the contractile responses to calcium ions in partially depolarized rabbit aortic strips. Both also blocked, but only by approximately 50%, the responses to noradrenaline and histamine in normal calcium medium. The responses to these agonists in calcium-free EGTA medium were also blocked partially. Cytochalasin-B partially blocked the acetylcholine-induced relaxation of aortic strips precontracted with phenylephrine but not the relaxation due to nitroglycerine or compound A 23187. The relaxation due to isoprenaline was potentiated by cytochalasin B. Since both compounds are known to block hexose transport but share no other known effects, it is suggested that a glycolytic intermediate could be required for the contraction in response to calcium. However, the concentrations of cytochalasin-B required for these effects were somewhat greater than those usually required to block hexose transport.

Original language	English
Pages (from-to)	153-157
Number of pages	5
Journal	European Journal of Pharmacology
Volume	144
Issue number	2
DOIs	https://doi.org/10.1016/0014-2999(87)90514-0
Publication status	Published - Dec 1 1987

Bibliographical note

Funding Information:
We have recently reported that cytochalasin-B (cyto-B) and phloretin (phlor) block the inotropic effect of digitalis and of compound BAY K-8644, an inotropic drug which holds open the calcium channels in cardiac muscle (Dresel and Ogbaghebriel, 1986; Dresel, 1986). Neither drug alone had any significant effect on isolated rabbit atria and papillary muscles. Although cyto-B caused a small change in K D for nitrendipine binding, we concluded that much of the activity of the two drugs could best be accounted for by a 'post-receptor' effect. We suggest that a mechanism requiring glucose is involved because the only known shared effect of the drugs is blockade i Aided by grants from the Medical Research Council of Canada and the Nova Scotia Heart Foundation. * To whom all correspondence should be addressed.

ASJC Scopus Subject Areas

Pharmacology

PubMed: MeSH publication types

Journal Article
Research Support, Non-U.S. Gov't

Access to Document

10.1016/0014-2999(87)90514-0

Cite this

@article{c5bdf0e0ff514e9586801acb64383347,

title = "Cytochalasin-B and phloretin depress contraction and relaxation of aortic smooth muscle",

abstract = "Cytochalasin-B (20 μM) and phloretin (100 μM) blocked by more than 80% the contractile responses to calcium ions in partially depolarized rabbit aortic strips. Both also blocked, but only by approximately 50%, the responses to noradrenaline and histamine in normal calcium medium. The responses to these agonists in calcium-free EGTA medium were also blocked partially. Cytochalasin-B partially blocked the acetylcholine-induced relaxation of aortic strips precontracted with phenylephrine but not the relaxation due to nitroglycerine or compound A 23187. The relaxation due to isoprenaline was potentiated by cytochalasin B. Since both compounds are known to block hexose transport but share no other known effects, it is suggested that a glycolytic intermediate could be required for the contraction in response to calcium. However, the concentrations of cytochalasin-B required for these effects were somewhat greater than those usually required to block hexose transport.",

author = "Dresel, {Peter E.} and Leah Knickle",

note = "Funding Information: We have recently reported that cytochalasin-B (cyto-B) and phloretin (phlor) block the inotropic effect of digitalis and of compound BAY K-8644, an inotropic drug which holds open the calcium channels in cardiac muscle (Dresel and Ogbaghebriel, 1986; Dresel, 1986). Neither drug alone had any significant effect on isolated rabbit atria and papillary muscles. Although cyto-B caused a small change in K D for nitrendipine binding, we concluded that much of the activity of the two drugs could best be accounted for by a 'post-receptor' effect. We suggest that a mechanism requiring glucose is involved because the only known shared effect of the drugs is blockade i Aided by grants from the Medical Research Council of Canada and the Nova Scotia Heart Foundation. * To whom all correspondence should be addressed.",

year = "1987",

month = dec,

day = "1",

doi = "10.1016/0014-2999(87)90514-0",

language = "English",

volume = "144",

pages = "153--157",

journal = "European Journal of Pharmacology",

issn = "0014-2999",

publisher = "Elsevier",

number = "2",

}

TY - JOUR

T1 - Cytochalasin-B and phloretin depress contraction and relaxation of aortic smooth muscle

AU - Dresel, Peter E.

AU - Knickle, Leah

N1 - Funding Information: We have recently reported that cytochalasin-B (cyto-B) and phloretin (phlor) block the inotropic effect of digitalis and of compound BAY K-8644, an inotropic drug which holds open the calcium channels in cardiac muscle (Dresel and Ogbaghebriel, 1986; Dresel, 1986). Neither drug alone had any significant effect on isolated rabbit atria and papillary muscles. Although cyto-B caused a small change in K D for nitrendipine binding, we concluded that much of the activity of the two drugs could best be accounted for by a 'post-receptor' effect. We suggest that a mechanism requiring glucose is involved because the only known shared effect of the drugs is blockade i Aided by grants from the Medical Research Council of Canada and the Nova Scotia Heart Foundation. * To whom all correspondence should be addressed.

PY - 1987/12/1

Y1 - 1987/12/1

N2 - Cytochalasin-B (20 μM) and phloretin (100 μM) blocked by more than 80% the contractile responses to calcium ions in partially depolarized rabbit aortic strips. Both also blocked, but only by approximately 50%, the responses to noradrenaline and histamine in normal calcium medium. The responses to these agonists in calcium-free EGTA medium were also blocked partially. Cytochalasin-B partially blocked the acetylcholine-induced relaxation of aortic strips precontracted with phenylephrine but not the relaxation due to nitroglycerine or compound A 23187. The relaxation due to isoprenaline was potentiated by cytochalasin B. Since both compounds are known to block hexose transport but share no other known effects, it is suggested that a glycolytic intermediate could be required for the contraction in response to calcium. However, the concentrations of cytochalasin-B required for these effects were somewhat greater than those usually required to block hexose transport.

AB - Cytochalasin-B (20 μM) and phloretin (100 μM) blocked by more than 80% the contractile responses to calcium ions in partially depolarized rabbit aortic strips. Both also blocked, but only by approximately 50%, the responses to noradrenaline and histamine in normal calcium medium. The responses to these agonists in calcium-free EGTA medium were also blocked partially. Cytochalasin-B partially blocked the acetylcholine-induced relaxation of aortic strips precontracted with phenylephrine but not the relaxation due to nitroglycerine or compound A 23187. The relaxation due to isoprenaline was potentiated by cytochalasin B. Since both compounds are known to block hexose transport but share no other known effects, it is suggested that a glycolytic intermediate could be required for the contraction in response to calcium. However, the concentrations of cytochalasin-B required for these effects were somewhat greater than those usually required to block hexose transport.

UR - http://www.scopus.com/inward/record.url?scp=0023499861&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023499861&partnerID=8YFLogxK

U2 - 10.1016/0014-2999(87)90514-0

DO - 10.1016/0014-2999(87)90514-0

M3 - Article

C2 - 3436365

AN - SCOPUS:0023499861

SN - 0014-2999

VL - 144

SP - 153

EP - 157

JO - European Journal of Pharmacology

JF - European Journal of Pharmacology

IS - 2

ER -

Cytochalasin-B and phloretin depress contraction and relaxation of aortic smooth muscle

Abstract

Bibliographical note

ASJC Scopus Subject Areas

PubMed: MeSH publication types

Access to Document

Other files and links

Fingerprint

Cite this