Effects of heptanol and carbenoxolone on noradrenaline induced contractions in guinea pig vas deferens
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Title |
Effects of heptanol and carbenoxolone on noradrenaline induced contractions in guinea pig vas deferens
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Creator |
PALANI, D
GHILDYAL, PARA MANCHANDA, R |
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Subject |
guineapig vas deferens
noradrenaline gap junction carbenoxolone |
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Description |
We examined the effects of two putative gap junction blockers, heptanol and carbenoxolone, on noradrenaline-induced contractions in guinea pig vas deferens. The force generated due to the exogenously added noradrenaline (20 μM) consisted of two components: the tonic and the oscillatory. 2 mM heptanol abolished the oscillatory contractions and drastically suppressed both the maximum force (by 85.4 ±18.2%) as well as the tonic component (by 28.8 ± 5.1%) (P < 0.01, n = 7). However, the effects of carbenoxolone (50 μM) were strikingly different, with the spikes of the oscillatory component being merged into a steady, “fused” contraction, without affecting the maximum force developed. The L-type Ca2+ channel blocker nifedipine (2 μM) abolished the oscillatory component of the contractions and significantly reduced the maximum force and tonic component (by 82.4 ± 6.8% and 19.7 ± 6.4% respectively; P < 0.01, n = 4), in a manner similar to that elicited by heptanol. Our results indicate that (i) while carbenoxolone specifically blocks gap junctions, heptanol appears to exert its actions through non-gap junctional mechanisms, possibly by blocking VGCCs in smooth muscle; (ii) gap junctions play a significant modulatory role in the generation of noradrenaline-induced contractions in guinea pig vas deferens, particularly in the emergence of oscillatory contractions, while the maximum force developed may be independent of gap junctional contribution.
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Publisher |
Elsevier
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Date |
2009-04-24T09:14:20Z
2011-12-08T06:29:56Z 2011-12-26T13:01:38Z 2011-12-27T05:45:42Z 2009-04-24T09:14:20Z 2011-12-08T06:29:56Z 2011-12-26T13:01:38Z 2011-12-27T05:45:42Z 2007 |
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Type |
Article
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Identifier |
Autonomic Neuroscience 137(1-2), 56-62
1566-0702 10.1016/j.autneu.2007.07.003 http://hdl.handle.net/10054/1238 http://dspace.library.iitb.ac.in/xmlui/handle/10054/1238 |
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Language |
en
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