Coupling of alpha(1)-Adrenoceptors to ERK1/2 in the Human Prostate

Introduction: alpha(1)-Adrenoceptors are considered critical for
the regulation of prostatic smooth muscle tone. However, previous
studies suggested further alpha(1)-adrenoceptor functions besides
contraction. Here, we investigated whether alpha(1)-adrenoceptors
in the human prostate may activate extracellular signal-regulated
kinases (ERK1/2). Methods: Prostate tissues from patients
undergoing radical prostatectomy were stimulated in vitro.
Activation of ERK1/2 was assessed by Western blot analysis.
Expression of ERK1/2 was studied by immunohistochemistry. The
effect of ERK1/2 inhibition by U0126 on phenylephrine-induced
contraction was studied in organ-bath experiments. Results:
Stimulation of human prostate tissue with noradrenaline (30 mu M)
or phenylephrine (10 mu M) resulted in ERK activation. This was
reflected by increased levels of phosphorylated ERK1/2. Expression
of ERK1/2 in the prostate was observed in smooth muscle cells.
Incubation of prostate tissue with U0126 (30 mu M) resulted in
ERK1/2 inhibition. Dose-dependent phenylephrine-induced contraction
of prostate tissue was not modulated by U0126. Conclusions:
alpha(1)-Adrenoceptors in the human prostate are coupled to ERK1/2.
This may partially explain previous observations suggesting a role
of alpha(1)-adrenoceptors in the regulation of prostate growth.
Copyright (C) 2011 S. Karger AG, Basel