1. Age-related changes in the reactivity of postsynaptic alpha-adrenoceptors of isolated portions (epididymal and prostatic) and in whole vas deferens have been studied using 4, 12 and 20 month-old @entity35 . 2. The pD2 values for @entity1425 -induced contractions were reduced in the epididymal portion and whole vas deferens of middle-aged and old animals, but not in the prostatic portion. No age related change to @entity2647 or @entity1338 sensitivity was observed. 3. pA2 values of @entity3159 and @entity3160 were not changed by aging in any preparation. @entity5521 pA2 values were reduced in the epididymal portion and in the whole vas deferens when @entity1425 , but not when @entity2647 concentration-response curves were displaced by the antagonist. The mean pA2 value of @entity3160 (6.78) indicates that this antagonist blocks alpha(1)-adrenoceptors in the @entity35 vas deferens. 4. The data presented here suggest that age-related decreases in the sensitivity to @entity1425 and @entity5521 (when measured by displacing @entity1425 concentration-effect curves) in the whole vas deferens are probably due to a variation in the proportion of alpha(1)-adrenoceptor subtypes in the epididymal portion of the @entity35 vas deferens.

Age-related changes in the reactivity of postsynaptic adrenoceptors in the XXXX vas deferens: differences between the epididymal and prostatic portion.

@entity3160 :: ('MESH:D015016', 'Chemical') :: ['yohimbine'] @entity1338 :: ('MESH:D003000', 'Chemical') :: ['clonidine'] @entity1425 :: ('MESH:D004837', 'Chemical') :: ['adrenaline'] @entity3159 :: ('MESH:D011224', 'Chemical') :: ['prazosin'] @entity5521 :: ('MESH:D010646', 'Chemical') :: ['Phentolamine', 'phentolamine'] @entity2647 :: ('MESH:D010656', 'Chemical') :: ['phenylephrine'] @entity35 :: ('10116', 'Species') :: ['rat', 'rats']
@entity35 :: (10116,Species) :: ['rat']
