Gap junction-dependent and -independent EDHF-type relaxations may involve smooth muscle cAMP accumulation

We have compared the mechanisms that contribute to endothelium-derived hyperpolarizing factor (EDHF)-type responses induced by ACh and the Ca(2+) ionophore A-23187 in the rabbit iliac artery. Relaxations to both agents were associated with ~1.5-fold elevations in smooth muscle cAMP levels and were attenuated by the adenylyl cyclase inhibitor 2',5'-dideoxyadenosine (DDA) and potentiated by the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Mechanical responses were inhibited by coadministration of the Ca(2+)-activated K(+) channel blockers apamin and charybdotoxin, both in the absence and presence of IBMX, but were unaffected by blockade of ATP-sensitive K(+) channels with the sulphonylurea glibenclamide. Relaxations and elevations in cAMP evoked by ACh were abolished by 18alpha-glycyrrhetinic acid, which disrupts gap junction plaques, whereas the corresponding responses to A-23187 were unaffected by this agent. Consistently, in "sandwich" bioassay experiments, A-23187, but not ACh, elicited extracellular release of a factor that evoked relaxations that were inhibited by DDA and potentiated by IBMX. These findings provide evidence that EDHF-type relaxations of rabbit iliac arteries evoked by ACh and A-23187 depend on cAMP accumulation in smooth muscle, but involve signaling via myoendothelial gap junctions and the extracellular space, respectively.

Medienart:

Artikel

Erscheinungsjahr:

2002

Erschienen:

2002

Enthalten in:

Zur Gesamtaufnahme - volume:282

Enthalten in:

American journal of physiology. Heart and circulatory physiology - 282(2002), 4 vom: 15. Apr., Seite H1548-55

Sprache:

Englisch

Beteiligte Personen:

Chaytor, Andrew T [VerfasserIn]
Taylor, Hannah J [VerfasserIn]
Griffith, Tudor M [VerfasserIn]

Themen:

1-Methyl-3-isobutylxanthine
115422-61-2
24345-16-2
37H9VM9WZL
Acetylcholine
Apamin
Biological Factors
Calcimycin
Charybdotoxin
Cyclic AMP
E0399OZS9N
Endothelium-dependent hyperpolarization factor
Glyburide
Journal Article
N9YNS0M02X
NG-Nitroarginine Methyl Ester
Phosphodiesterase Inhibitors
Potassium Channel Blockers
Research Support, Non-U.S. Gov't
SX6K58TVWC
TBT296U68M
V55S2QJN2X

Anmerkungen:

Date Completed 09.05.2002

Date Revised 30.09.2020

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM117775770