Browsing by Author "ROHDE, GC"

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    ASYMMETRIC DISTRIBUTION OF PURINERGIC AND ADRENERGIC NEUROTRANSMISSION COOPERATES IN THE MOTOR-ACTIVITY ALONG THE RAT VAS-DEFERENS
    (1986) ROHDE, GC; VENEZIAN, E; HUIDOBROTORO, JP
    The distribution of purinergic and adrenergic responses in the epididymal and prostatic segment of the rat vas deferens were studied in vitro. Prazosin antagonizes the twitch elicited by electrical stimulation mainly in the epididymal segment while .alpha.,.beta.-methyleneadenosine 5''-triphosphate (.alpha.,.beta.-mATP) preferentially inhibits the response of the prostatic segment. Using both prazosin plus .alpha.,.beta.-mATP, the response to field stimulation was completely inhibited. Concentration response curves revealed that adrenergic compounds elicited a greater contraction in the epididymal portion than in the prostatic end of the ductus. Purinergic compounds caused a contraction of greater magnitude in the prostatic portion. The results suggest that adrenergic and purinergic mechanisms are asymmetrically distributed along the vas deferens reflecting a gradient of adrenergic and purinergic receptors along the ductus.
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    PURINERGIC SUPERSENSITIVITY FOLLOWING SYMPATHECTOMY ADDS FURTHER SUPPORT TO CO-TRANSMISSION IN THE RAT VAS-DEFERENS
    (1988) ROHDE, GC; HUIDOBROTORO, JP
    Adrenergic and purinergic compounds contract the longitudinal muscles of the rat vas deferens. Whereas ATP and related purinergic analogs produced contractions of greater magnitude in the prostatic half as compared to that of the epididymal end, the magnitude of the .alpha.1-adrenoceptor-induced responses was larger in the epididymal than in the prostatic half of the rat ductus. Chemical sympathectomy following a 48 hr 6-hydroxydopamine-treatment (6-OHDA) caused a leftward displacement of the concentration-response curves for adrenergic and purinergic drugs, this effect being more evident in the prostatic segment. Sympathectomy caused a significant increase in the maximal response induced by ATP and adrenergic compounds which was more evident in the prostatic half of the rat ductus. The denervation-induced supersensitivity was stimulus-specific since angiotensin II and acetylcholine showed no significant change in potency. In the case of bradykinin, there ws a manifest increase in the maximal response of the prostatic segment of the ductus of the chemically denervated tisses. In addition, denervation also caused an increase in the potency of prazosin and phentolamine as .alpha.1-adrenoceptor blocking agents; denervation did not change the potency of yohimbine as an .alpha.2-adrenoceptor blocker.