Targeted disruption of the endothelin-B-receptor gene attenuates inflammatory nociception and cutaneous inflammation in mice.
Endothelin-1 (ET-1) has been suggested to have a potential function as an inflammatory mediator. The study reported here assessed the putative inflammatory/nociceptive actions of the ET isopeptides using endothelin-B (ET(B))-receptor knockout (KO) mice and ET(A)- (SB 234551) and ET(B)- (A192621) selective antagonists. Phenylbenzoquinone (PBQ)-induced algesia was evident in the wild-type (WT) ET(B) (+/+) mice, attenuated by 80% in the heterozygous ET(B) (+/-) mice, and absent in the ET(B) (-/-) homozygotes. This was reproduced pharmacologically in WT ET(B) (+/+) mice where the algesic effect of PBQ was inhibited 74% by A192621, but unaffected by SB 234551 (both at 25 mg/kg p.o.). Similar observations were made in a model of cutaneous inflammation: ET(B) (+/+) mice had a marked inflammatory response to topical arachidonic acid, ET(B) (+/-) and ET(B) (-/-) mice had significantly reduced edema responses (37% and 65% inhibition). Neutrophil infiltration was reduced in the ET(B) (+/-) and ET(B) (-/-) mice (51% and 65% reduction, respectively). Topical administration of A192621 (500 microg/ear) inhibited arachidonic acid-induced swelling (39%) in WT ET(B) (+/+) mice. Collectively, these results support a role for the ET(B)-receptor in the mediation of inflammatory pain and cutaneous inflammatory responses. As such, the development of ET(B)-receptor-selective antagonists may be of therapeutic utility in the treatment of inflammatory disorders.
Griswold
D E
DE
Department of Pulmonary Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406-0939, USA.
Douglas
S A
SA
Martin
L D
LD
Davis
T G
TG
Davis
L
L
Ao
Z
Z
Luttmann
M A
MA
Pullen
M
M
Nambi
P
P
Hay
D W
DW
Ohlstein
E H
EH
D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D016227:Benzoquinones / Q000494:pharmacology; D003872:Dermatitis / Q000209:etiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D010146:Pain / Q000209:etiology*; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000235:genetics / Q000502:physiology*
D016227:Benzoquinones; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; D016718:Arachidonic Acid; C029322:phenylbenzoquinone