Alpha adrenergic stimulation modified prostaglandins release in vas deferens.

Methoxamine enhanced contractions of mouse vasa deferentia through alpha adrenoceptor stimulation. Additionally, the generation of PGF-like material by the tissue was increased by methoxamine, whereas that of PGE-like material was decreased. The effects of methoxamine on prostaglandin output (stimulation and depression) were antagonized by yohimbine and phenoxybenzamine. Moreover, the stimulating influence of methoxamine on the contractile activity of the preparations was attenuated by the prostaglandin synthesis inhibitors indomethacin and acetylsalicylic acid. The results suggest that methoxamine is able to modify prostaglandin synthesis and output in mouse vasa deferentia, probably through an alpha adrenergic mediated mechanism coupled to the prostaglandin synthesizing system. The fact that indomethacin and acetylsalicylic acid blocked alpha stimulatory responses to methoxamine, suggest a modulatory role for endogenous prostaglandins. Since methoxamine increased PGF levels, this prostaglandin might potentiate the contractile influence of methoxamine.