Cell-to-cell signa transduction (cross talk) via ATP on prostate

本研究观察了嘌呤受体激动剂对内源性去甲肾上腺素（NA）诱发电场刺激大鼠前列腺释放的影响。采用高效液相色谱-电化学检测技术定量测定NA含量。1)大鼠前列腺肾上腺素能神经末梢有两种嘌呤受体（PI和P?）抑制na释放。2)高频EPS （8 Hz）诱发NA诱导嘌呤通过a受体在效应细胞上释放。EPS引起的嘌呤释放量高于NA释放量（总嘌呤：NA= 100: 1）。3)效应细胞上a受体刺激引起的嘌呤影响突触前嘌呤受体（PI和P?），抑制NA释放。4)通过膜前嘌呤受体抑制na释放，导致前列腺平滑肌张力降低。5)这些结果表明，高频EPS诱导的过量NA可诱导过度收缩的效应细胞释放大量嘌呤，从而抑制NA的释放，降低收缩张力。肾上腺素能神经在控制前列腺平滑肌张力中起重要作用。众所周知，在大多数组织中，na的释放是通过突触前a2-肾上腺素受体的反馈抑制来调节的。然而，很少有人尝试研究通过前列腺前膜嘌呤受体对神经传递的调节。在这项研究中，我们提出了来自效应细胞的嘌呤的跨突触神经调节的存在。

In this study, the effects of purinoceptor agonists on the release of endogenous noradrenaline (NA) evoked electrical field stimulation (EPS) prostate gland of the rat were examined. NA was quantified by HPLC coupled with electrochemical detection techniques. 1) There are two kind of purinoceptors (PI and P?) inhibiting NA-release on adrenergic nerve terminals in rat prostate. 2) NA evoked by high-frequency EPS (8 Hz) induces purines-release via a, receptor on effector cells. The amount of purines-release evoked by EPS was higher than that of NA-release (total purines : NA= 100 : 1). 3) Purines evoked by stimulation of a, receptor on effector cells affect prejunctional purinoceptor (PI and P?), and inhibit NA-release. 4) Inhibition of NA-release via prejunctional purinoceptors consequently induces the decreases of the tone in prostate smooth muscle. 5) These results indicate that excess NA evoked by high frequency EPS induced abundant purines-release from effector cells with excess contraction, and consequently inhibit NA- release and decrease the tone of contraction.The adrenergic nerve plays an important role in the control of prostate smooth muscle tone. It is well known that NA-release is regulated by feedback inhibition through prejunctional a2-adrenoceptors in most tissues. However, very few attempts have been made to investigate the regulation of neurotransmission through prejunctional purinoceptors in the prostate. In this investigation, we suggested the existence of transsynaptic neuromodulation by purines derived from effector cells.