EFFECT OF GREEN TEA (CAMELLIA-SINENSIS) EXTRACT ON THE RAT DIAPHRAGM

The effect of hot water extract of green tea on skeletal muscle and it s neurotransmission was studied employing innervated and denervated ra t diaphragm. Green tea extract (GTE) has a facilitatory effect at lowe r concentrations and a paralytic effect at higher concentrations on sk eletomotor function. GTE did not have any effect on direct twitch resp onses or on acetylcholine (ACh) and KCl induced contractures of denerv ated rat diaphragm and it antagonised the submaximal paralytic effect of D-tubocurarine and decamethonium. GTE-induced facilitation and inhi bition were nullified in the presence of magnesium chloride. Nifedipin e, reduced GTE-induced facilitation as well as inhibition of twitch re sponses as a function of its concentration. It was suggested that GTE might act on Ca2+ channels at the skeletomotor junction. The effect of crude polyphenol on neuromuscular junctions was found to be similar t o that of GTE. Therefore, it is suggested that the crude polyphenol co ntent of GTE was the active constituent responsible for its effect on neuromuscular junction. (C) 1997 Elsevier Science Ireland Ltd.