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Target Concepts:
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Query: UMLS:C0231530 (
twitching
)
2,043
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
This study compared the effects of
endothelin-1
(
ET-1
), ET-2 and ET-3 on the guinea pig field-stimulated ileum. All ETs (0.3-30 nM) caused graded inhibitions of nerve-mediated responses followed by sustained contractions. The rank order of potencies for the twitch depressor effect (IC50S) was ET-3 =
ET-1
greater than ET-2, with ET-3 causing greater maximal inhibition than
ET-1
or ET-2. The rank order of potencies for contraction (EC50S) was
ET-1
= ET-2 greater than ET-3, with
ET-1
causing greater maximal contraction than ET-2 or ET-3.
Twitch
inhibition by
ET-1
(3 nM) was unaffected by indomethacin (5.6 microM), cromakalim (10 microM), glibenclamide (3 microM) or nicardipine (0.1 microM).
ET-1
-induced contraction was unaltered by tetrodotoxin (0.3 microM), atropine (0.3 microM) or glibenclamide, but was reduced by indomethacin. Cromakalim and nicardipine virtually abolished
ET-1
-induced contraction.
ET-1
(up to 30 nM) did not potentiate submaximal contractions induced by acetylcholine, histamine, bradykinin or substance P. ET-3 relaxed ileal segments precontracted with either acetylcholine (0.3 microM) or histamine (1 microM). Pretreatment of guinea pigs with pertussis toxin (50 micrograms/kg i.p., 6 days beforehand) did not influence either effects of
ET-1
on the field-stimulated ileum. Our data suggest that the dual effects of ETs on the guinea pig isolated ileum are mediated by distinct receptors and possibly involve different mechanisms of action. The transient inhibition of responses to field stimulation seems unrelated to activation of ATP-sensitive potassium channels and is rather insensitive to L-type Ca++ channel blockade.
...
PMID:Dual effects of endothelins -1, -2 and -3 on guinea pig field-stimulated ileum: possible mediation by two receptors coupled to pertussis toxin-insensitive mechanisms. 137 59
The role of endothelin receptor subtypes, i.e., ET(A) and ET(B) receptors, in the behavioral effects of the intracerebroventricular (ICV) administration of
endothelin-1
were examined in conscious rats. ICV administration of
endothelin-1
(1-9 pmol/rat) dose dependently produced barrel rolling and other convulsive behaviors including bodily
twitching
, rigidity, back crawling, fore/hindlimb dystonia, fore/hindlimb clonus, tail extension, and facial clonus. Moreover, a marked increase in spontaneous locomotor activity was observed in animals that were treated with a low dose of
endothelin-1
(1 pmol/rat, ICV). Endothelin-1 (9 pmol/rat, ICV)-induced barrel rolling and other convulsive behaviors were completely suppressed by the coadministration of BQ-123 (15 nmol, ICV), a specific endothelin ET(A) receptor antagonist, but not of BQ-788 (15 nmol/rat, ICV), a specific endothelin ET(B) receptor antagonist. In contrast, increased locomotor activity produced by treatment with a low dose of
endothelin-1
(1 pmol/rat, ICV) was antagonized by coadministration of BQ-788, but not of BQ123. These results indicate that
endothelin-1
, which has affinity for both endothelin ET(A) and ET(B) receptors, most likely acts on central ET(A) receptors to evoke barrel rolling and other convulsive behaviors. In addition, activation of central ET(B) receptors may be involved in the increase in spontaneous locomotor activity. These results suggest that brain endothelin receptor subtypes may be involved in the regulation of various physiological functions.
...
PMID:Role of endothelin receptor subtypes in the behavioral effects of the intracerebroventricular administration of endothelin-1 in conscious rats. 1049 13
