Fj. Pereira et al., COMPARATIVE REGULATION OF ALPHA(1)-ADRENERGIC RECEPTOR-MEDIATED CONTRACTION IN UROGENITALLY DERIVED SMOOTH-MUSCLE - EFFECT OF EPIDERMAL GROWTH-FACTOR, Urological research, 25, 1997, pp. 13-19
Contractility of smooth muscle within mammalian urogenital organ syste
ms has an established role in physiological/pathophysiological functio
ning of the component structures. Our aim was to examine the direct ef
fect of epidermal growth factor (EGF) on smooth muscle tone as well as
its indirect effects in regulating alpha(1)-adrenoceptor-mediated con
traction of the prostate, the vas deferens and renal arteries. Tissues
were mounted isometrically, under controlled conditions, and changes
in tension in response to treatment with phenylephrine (PE) with or wi
thout pretreatment with EGF were recorded on a physiological recorder
via force transducers. In the rabbit prostate, EGF potentiated the mag
nitude of contraction to PE. The potentiation appeared to be dependent
on cycle-oxygenase products. In the human prostate, EGF potentiated t
he contractile response to PE. EGF had no effect on the PE-induced con
traction of the rabbit renal artery and vas deferens. EGF alone did no
t alter smooth muscle tone in any of the above-mentioned tissues. The
main finding of this study is the difference in the regulation by EGF
of the alpha(1)-adrenoceptor-mediated response in smooth muscle of the
prostate, from that by the vas deferens and renal artery. The reasons
for this difference in response remain to be elucidated. This study m
ay form the basis for further investigation into receptor transregulat
ion and its relevance to symptomatic benign prostatic hyperplasia (BPH
).