The Theaflavin Fraction is Responsible for the Facilitatory Effect of Black Tea at the Skeletal Myoneural Junction
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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| Title |
The Theaflavin Fraction is Responsible for the Facilitatory Effect of Black Tea at the Skeletal Myoneural Junction
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| Creator |
Basu, S
Choudhuri, T Chauhan, S P S Dasgupta, A K Choudhuri, L Vedasiromoni, J R |
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| Subject |
Drug Development/Diagnostics & Biotechnology
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| Description |
The effect of various fractions of black tea [(Camellia Sinensis) (L) O. Kuntze (Theaceae)] on the function of
mammalian skeletomotor apparatus was studied. The theaflavin fraction (Tfs) produced a concentrationdependent
facilitation of indirect twitch responses of the rat phrenic nerve diaphragm preparation and the
facilitation was dependent on the amount of calcium present in the bathing fluid. Nifedipine reduced the
facilitatory effect of Tfs as a function of its concentration. Tfs failed to produce facilitation when the twitch height
was reduced to about 50% of the control value in presence of magnesium chloride. Tfs completely antagonized the
submaximal paralytic effect of d- tubocurarine and decamethonium bromide. Tfs did not have any effect on direct
twitch responses or on acetylcholine (Ach) and potassium chloride (KCl) induced contractures of denervated
diaphragm. The results revealed that the site of action of Tfs is on the contractile mechanism of the voluntary
muscle and point to a critical role of calcium in the mechanism of action of Tfs. NN-nitro-L-arginine-methyl ester
(L-NAME), a nitric oxide synthase (NOS) inhibitor, antagonized both the facilitatory and inhibitory effects on
indirect twitch responses of rat diaphragm induced by L-arginine and Tfs when the phrenic nerve was stimulated at
5 Hz and 50 Hz respectively. The thearubigin (Trs) fraction of black tea and the aqueous part which is completely
devoid of Tfs, did not potentiate the twitch responses. The findings suggest that Tfs have a potentiating effect on
the contractile mechanism of skeletal muscle and that calcium and nitric oxide may modulate this action of Tfs.
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| Date |
2005
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/1182/1/LIFE_SCIENCES__Volume_76___Issue_26___Pages_3081%2D3088__[62].pdf
Basu, S and Choudhuri, T and Chauhan, S P S and Dasgupta, A K and Choudhuri, L and Vedasiromoni, J R (2005) The Theaflavin Fraction is Responsible for the Facilitatory Effect of Black Tea at the Skeletal Myoneural Junction. Life Sciences, 76 (26). pp. 3081-3088. |
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| Relation |
http://dx.doi.org/10.1016/j.lfs.2004.12.018
http://www.eprints.iicb.res.in/1182/ |
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