The effect of frusemide on oxytocin-induced contractions of the rat myometrium.
Oxytocin-induced contractions of isolated strips of oestradiol-treated rat myometrium were found to be affected by exposure to the diuretic frusemide. At a concentration of 20 microM. frusemide transiently increased the force of contraction over a period of approximately 10 min. After this time there was a progressive fall in contractile force. At a higher concentration of 200 microM, only the progressive fall in force was seen until contractions were completely abolished. Frusemide has been reported to increase the activity of cAMP-phosphodiesterase in tissue extracts from oestradiol-treated rat myometrium. Therefore, the changes in contraction due to exposure to frusemide may be a reflection of the changes in intracellular cAMP resulting from a stimulation of cAMP-phosphodiesterase activity. In support of this idea, addition of dibutyryl cAMP was found to partially restore contractions after frusemide treatment. These data suggest that frusemide may be a useful tool in the manipulation of tissue cAMP levels in order to determine the different roles of cAMP in the oestradiol-treated rat myometrium.
Mozhayeva
M G
MG
Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences, St. Petersburg, Russia.
Bagrov YaYu
Ostretsova
I B
IB
Gillespie
J I
JI
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D005665:Furosemide / Q000494:pharmacology*; D066298:In Vitro Techniques; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D010121:Oxytocin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014590:Uterine Contraction / Q000187:drug effects*
D010121:Oxytocin; D003994:Bucladesine; D005665:Furosemide; D000242:Cyclic AMP