engleski

Do neurotransmitter receptors change their function and signaling mechanism in vivo?

We found that hemicastration induces functional changes of ovarian muscarinic receptors, i.e., they become involved in the compensatory growth of the remaining ovary and change their signaling mechanism. In the first group of experiments nulliparous, Wistar rats underwent unilateral ovariectiomy. Ten days later, wet weight, protein content and concentrations of total nucleic acids of the remnant ovaries were determined. Bilateral abdominal vagotomy and muscarinic antagonists tirhexyphenidyl or propantheline completely aboished compensatory growth. The effect of propantheline was dose-dependent and could be reversed by carbachol of bethanecol. In the second study, 1,2 diacylglycerol (DAG) levels in the remnant ovaries were, as measured 15 minutes following the operation, increased especially (by3-4-fold) if organs were incubated with carbachol. The hemicastration-induced increase was inhibited by atropine (iv) or botulinum toxin (into ovarian bursa) pretreatments, or by abdominal vogotomy, The effect of carbachol was inhibited by atropine, or by abdominal vagotomy performed prior to hemicastration. Carbachol, atropine, or botulinum toxin had no effects on DAG levels in the ovaries of the sham.-operated rats.

receptors; signaling; function

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