信州医誌，58⑶：103〜114，2010Expression ofα1‑Adrenergic Receptor Subtypes andAngiotensin II Type 1 Receptor in the Prostate of
Spontaneously Hypertensive Rats
Tsuyoshi NAKAYAMA , Tetsuya IMAMURA, Osamu ISHIZUKA
and Osamu NISHIZAWA
Department of Urology, Shinshu University School of Medicine

Background :To clarify the mechanisms of lower urinary tract symptoms (LUTS) associated with benign
prostate hyperplasia (BPH),we investigated the expression of α1‑adrenergic receptor (AR)subtypes and theangiotensin II type 1 receptor (AT1)within the prostate of spontaneously hypertensive rats (SHRs).
Methods:Twelve male 25‑week‑old SHRs and Wistar Kyoto (WKY)rats were randomly separated into twogroups (n =6 each).One group was given 20 ml 0.9% sodium chloride solution (saline)orallyper kg‑bodyweightdaily for one week. The other group received no treatment. After 7 days of saline loading, systolic bloodpressure (SBP)and prostate weight were measured.The prostates were immunohistochemically analyzed for
α1‑AR subtypes and AT1.
Results:After 7 days, the SBP and prostate weight of saline‑loaded SHRs tended to increase, but was not
signiﬁcantly diﬀerent compared to the untreated rats.The expression ofα1‑AR subtypes and AT1 within theprostates of saline‑loaded SHRs was higher than in the untreated ones. In contrast, the expression in thesaline‑loaded WKY rat prostates did not increase compared to the untreated ones.
Conclusion : Increased numbers of α1‑AR subtypes and AT1 in saline‑loaded SHR prostates might play
important roles in the development of LUTS associated with BPH. Shinshu Med J 58 : 103 ―114, 2010
(Received for publication February 2, 2010;accepted in revised form February 16, 2010)
Key words:spontaneously hypertensive rats, benign prostate hyperplasia,
α1‑adrenergic receptor subtypes, angiotensin II type 1 receptor

Introduction

relationship(s)between persistent hypertension and
BPH are not clear.

Persistent hypertension is a risk factor for stroke,

Spontaneously hypertensive rats (SHRs), whichheart attack, heart failure, and arterial aneurysm

are used as a model of cardiovascular disease ,and is a leading cause of chronic renal failure. It

also develop erectile dysfunction

increases not only the risk of developing cardiovas-

hypertrophy . The rat prostate consists of ﬁve

cular disease and diabetes, but also that of lower

lobes:the ventral,lateral type 1,lateral type 2,andurinary tract symptoms (LUTS). In clinical cases,

dorsal lobes, as well as the coagulating gland .We

many patients complaining of LUTS due to benign

focused on the expression of α1‑adrenergic rece-

prostate hypertrophy (BPH) or overactive bladderptor (AR) subtypes and angiotensin

have persistent hypertension . However, theptor (AT1) in the prostatic ventral and lateral‑and prostatetype 1 rece-

dorsal lobes of SHRs.Theα1‑AR subtypes regulate
Corresponding author:Tsuyoshi Nakayama
Department of Urology, Shinshu University School ofcell growth as well as mediate prostate smooth

M edicine, 3‑1‑1 Asahi, M atsumoto‑city,

muscle contraction in the human prostate . The

Nagano‑prefecture, 390‑8621, Japanangiotensin

No. 3, 2010

peptide increases blood pressure103

Nakayama ･ Imamura ･ Ishizuka et al.

and binds to at least two receptor subtypes, AT1

rats were anesthetized with intraperitoneal

and angiotensin Ⅱ type 2 receptor (AT2). It also

ketamine hydrochloride (75 mg/kg body weight,

promotes cell growth and smooth muscle tone

Sankyo Eeru Medicine. Co., Tokyo, Japan) andwithin the prostate.Previously,we showed thatxylazine (15 mg/kg body weight, Bayer, Lever-oral loading with 0.9 % sodium chloride solution

kusen, Germany). The prostate was removed along(saline) increases the expression of tachykinins,with the urinary bladder, urethra, and seminaltransient receptor potential vanilloid 1 (TRPV1),

gland.The animals were then euthanized by inhala-

and P2X3 purine receptors within the urinary blad-tion of diethyl ether as approved by the Animal

der of SHRs . These rats then develop detrusor

Ethics Committee.The urinary bladder and seminal

overactivity . In this study we investigatedgland were resected from the prostate, which waswhether the expression of the α1‑AR subtypes andthen weighed.

AT1 within the prostate of SHRs was also in-Dcreased by saline loading.
Materials and M ethods
A Animals

Immunohistochemistry
For immunohistochemistry, the prostates wererinsed with phosphate buﬀered saline (PBS) and
ﬁxed in 4% paraformaldehyde with 4% sucrose in
0.1 M phosphate buﬀer for 12 hours at 4°
C,and thenM ale SHRs (SHR/Izm, n =12, 350‑380 g, SLC

embedded in paraﬃn. Each sample was cut into 5

Inc., Shizuoka, Japan) and Wistar Kyoto rats

μm thick serial sections. The sections were

(WKY,n =12,390‑430 g,SLC Inc.,Shizuoka,Japan)

deparaﬃnized, rehydrated, and rinsed three times

at 25 weeks of age were used for these experiments.

with PBS for 5 minutes at 4°
C. Antigen retrieval

All were maintained under a 12‑hour alternating

was achieved byimmersion of the sections in 10 mM

light‑dark cycle with food and water ad libitum.

sodium citrate and microwaving at 100°
C for 5The animals were treated in accordance with The

minutes. The specimens were coated with 1.5%

National Institutes of Health Animal Care Guide-

normal donkey serum (Chemicon International Inc.,

lines and the guidelines approved by the Animal

Temecula,CA,USA)and 1.5% non‑fat milk in PBS

Ethics Committee of Shinshu University School offor 1 hour at 4°
C.Some sections were then incubated

Medicine.

with proliferative cell nuclear antigen (PCNA, 1:

B Administration of Saline Solution

250, mouse monoclonal, Thermo Fisher Scientiﬁc

The SHRs were randomly separated into two

Anatomical Pathology,Cheshire,UK),a marker forgroups (n =6 each). One, the saline‑loaded group,

proliferating cells. Other sections were incubated

was administered with 20 ml of 0.9 % sodium chlo-with anti‑angiotensin

ride solution (saline)per kg‑body weight daily for 7(Angitensin

days.The saline was delivered with a syringe via a

Novus Biologicals, Inc.,Littleton,UK)for 12 hours

stomach feeding tube inserted through the mouth.

at 4°
C. The sections were rinsed with PBS at 4°C,

The other group did not receive any treatment

and then incubated with donkey anti‑mouse IgG(untreatment controls). After 7 days of saline load-

secondary antibody conjugated with Alexa ﬂuor 594

ing, body weight was measured and systolic blood(1:250, Molecular Probes, Eugene, OR, USA)for 1

pressure (SBP) was indirectly measured with ahour at 4°
C. Following rinsing, double staining oftail‑cuﬀ apparatus (BP‑98A‑L, Softron, Tokyo,

each section was achieved by incubation with anti-

Japan)while the rats were quietly restrained with-bodies for the α1A adrenergic receptor (α1A‑AR,

out anesthesia in a plastic chamber.The WKY rats

1:250,rabbit polyclonal,Santa Cruz Biotechnology

were also treated as above.

Inc., Santa Cruz, CA, USA), the α1D adrenergic

C Tissue processing

receptor (α1D‑AR, 1:250, rabbit polyclonal, Santa

Following SBP measurement, the experimental
104

type 1 receptor antibody

receptor, 1:250, mouse monoclonal,

Cruz Biotechnology Inc.), or the α1B adrenergic
信州医誌 Vol. 58

α1‑adrenergic and angiotensin receptors

receptor (α1B‑AR, 1: 250, goat polyclonal, Santa

Prior to saline loading, there was no diﬀerence

Cruz Biotechnology Inc.)antibody for 12 hours at 4°

between the systolic blood pressures (SBP) of theC.After rinsing with PBS,theywere incubated withuntreated control and saline‑loaded groups (189.5±

donkey anti‑rabbit or anti‑goat IgG secondary

4.2 mmHg, 197.1±4.3 mmHg, respectively). After 7

antibody conjugated with Alexa ﬂuor 488 (1: 250,

days of saline loading,the SBP of the saline‑loaded

Molecular Probes) for 1 hour at 4°
C. Finally, cell

SHRs, 205.5±5.4 mmHg, tended to increase, but

nuclei were counterstained with 5 μg/ml 4ʻ
, 6‑

was not signiﬁcantly diﬀerent from the controls,

diamidino‑2‑phenylindole dihydrochloride (DAPI,

192.2±4.6 mmHg.At that time,the prostate weight

Molecular Probes). The slides were coated within saline‑loaded animals, 1.24±0.03 g, was not

Fluorescent M ounting M edium (Dako Cytomation,

signiﬁcantly diﬀerent from that of the controls,

Carpinteria, CA, USA). Other sections from

1.18±0.017 g.Also,the SBP (146.83±3.7 mmHg)andeach sample were stained with hematoxylin andthe prostate weight (1.23±0.05 g) of the saline‑

eosin (H&E) or the ApopTag

loaded WKY rats were not signiﬁcantly diﬀerent

ISOL ﬂuorescence

apoptosis detection (DNase Types I &,Chemiconfrom these of the controls (110.17 ±8.5 mmHg,

International Inc.) technique, which identiﬁes both1.36±0.08 g, respectively).

caspase‑dependent and ‑independent apoptosis. All

B Immunohistochemistry of the ventral lobes

samples were observed with a Leica DAS Micro-

At 7 days after saline loading, there were no

scope (Leica Microsystems GmbH, Wetzlar, Ger-

obvious diﬀerences between the prostate ventralmany). Also, we conﬁrmed that negative controls

lobes of the untreated (Fig. 1A) and saline‑loaded

without α1‑ARs and AT1 antibody were not visual-

SHRs (Fig.1B)when viewed bystandard bright ﬁeld

ized.

microscopy. Numerous proliferating epithelial cells

Observers, who were not aware of the treatment

in both groups were positive for PCNA antibody

status, made six observations of each sample, and(Fig. 1C,D), but there was no signiﬁcant diﬀerence

then semi‑quantitatively evaluated the presence ofbetween them (Table 1). There were one or two

ﬂuorescence markers in each observed area. The

caspase‑dependent and ‑independent apoptotic cells

numbers of PCNA‑positive cells and ﬂuorescently

present in both groups (Fig. 1E,F).

tagged spots were counted, and the observed areas
were estimated using Image‑Pro

The presence ofα1A‑,α1D‑,α1B‑ARs,and AT1Plus (Mediaon the epithelial cells in the ventral lobes were

Cybernetics, Inc., Bethesda, M D, USA). The den-visualized by immunohistochemistry (Fig. 2). The

sity of PCNA‑positive cells and ﬂuorescently tagg-

expression of α1A‑, α1D‑, and α1B‑ARs in theed spots was then calculated and expressed assaline‑loaded SHRs was signiﬁcantly higher than incells/μm or spots/μm .

the controls (Table 1). There was also signiﬁcantly

E Statistical Analysis

more epithelial AT1 in the ventral lobe of theResults were expressed as means ± standard

saline‑loaded SHRs compared to untreated controls

error of the means. The non‑repeated measures(Fig.2,Table 1).In contrast,the presence of α1A‑,

Studentʼ
s t‑test was used to compare untreated

α1D‑,α1B‑ARs,and AT1 in the ventral lobes of thecontrols with saline‑loaded SHRs. Repeated mea-

saline‑loaded WKY rats did not increase comparedsures Studentʼ
s t‑test was used to compare staining

to the untreated controls (Table 2).None of theα1‑of the ventral and laterodorsal prostate in each

AR subtypes appeared to co‑localize with the AT1.

group. Diﬀerences with P＜0.05 were considered

C Immunohistochemistry of lateral‑dorsal lobes

signiﬁcant.

At 7 days after saline loading, there were no
Results

A Blood pressure and prostate weightNo. 3, 2010

obvious diﬀerences between the prostate lateral‑
dorsal lobes of the untreated (Fig. 3A) and saline‑
loaded SHRs (Fig. 3B) when viewed by standard
105

Nakayama ･ Imamura ･ Ishizuka et al.

Fig.1
106

信州医誌 Vol. 58

α1‑adrenergic and angiotensin receptors
Table 1 PCNA‑positive cells,epithelial α1‑AR subtypes,and Angiotensin Ⅱ type 1 receptor in
the ventral and lateral‑dorsal lobes of SHR
Ventral lobe

Lateral‑dorsal lobe

Untreated

Saline‑loaded

Untreated

Saline‑loaded

PCNA positive cells (cells/μm )0.30±0.03

0.31±0.03

0.01±0.002

0.03±0.01

α1A adrenergic receptor (spots/μm )2.05±0.51

5.27±1.15

0.58±0.11

1.53±0.24

α1D adrenergic receptor (spots/μm )1.49 ±0.25

7.80±1.39

1.47±0.21

6.03±1.95

α1B adrenergic receptor (spots/μm )Angiotensin II type 1 receptor(spots/μm )1.31±0.19

2.73±0.27

1.81±0.18

6.08±1.24

0.35±0.03

0.58±0.11

1.09 ±0.23

6.20±2.54

P＜0.05, P＜0.01, compared with untreated control SHRs
P＜0.05, P＜0.01, compared with ventral prostate of untreated control SHRs
P＜0.05, P＜0.01, compared with ventral prostate of saline‑loaded SHRs

bright ﬁeld microscopy. The lateral‑dorsal lobe ofsigniﬁcantly more PCNA‑positive cells in the ven-

the untreated controls had few PCNA‑positive cells

tral lobes than in the lateral‑dorsal lobes (Table 1).

(Fig. 3C). In contrast, the same region of saline‑

The expression of the α1A‑ARs within the ventral

loaded SHRs had signiﬁcantlymore PCNA‑positive

lobe epithelial cells was also higher than that in thecells than controls (Fig. 3D, Table 1). One or twolateral‑dorsal lobes. In contrast, the expression of

caspase‑dependent and ‑independent apoptotic cells

neither the α1D‑ nor the α1B‑ARs within the ven-

were present in each group (Fig. 3E,F).

tral lobes was signiﬁcantlydiﬀerent from that in the

There were signiﬁcantly more α1A‑, α1D‑, andlateral‑dorsal lobes. However, expression of epith-

α1B‑ARs within the lateral‑dorsal lobe epithelium

elial AT1 within the ventral lobes was signiﬁcantlyof the saline‑loaded SHRs than in the untreatedlower than in the lateral‑dorsal lobes. In thecontrols (Fig. 4, Table 1). Also, there was signiﬁca-

untreated WKY rats, there were no diﬀerences

ntly more epithelial AT1 in the saline‑loaded SHRs

between ventral and lateral‑dorsal lobes (Table 2).

compared to the controls (Fig. 4, Table 1). In con-After 7 days of saline loading, the number of

trast, the presence of α1A‑ARs , α1D‑ ARs, α1B‑

PCNA‑positive proliferating cells in the ventral

ARs and AT1 in the lateral‑dorsal lobes of thelobes was signiﬁcantly greater than that in thesaline‑loaded WKY rats did not increase comparedlateral‑dorsal lobes (Table 1).The expression of theto the untreated controls (Table2).As in the ventral

α1A‑ARs within the ventral lobe epithelium waslobe, none of the α1‑AR subtypes appeared to co‑also signiﬁcantly greater than that in the lateral‑

localize with the AT1.

dorsal lobes. In saline‑loaded SHRs, there was no

DComparison between ventral and lateral‑

diﬀerence in the expression of theα1D‑AR between

dorsal lobes

the ventral and lateral‑dorsal lobes. However, theIn the untreated control SHRs, there wereexpression of both the α1B‑AR and the AT1 wasFig.1 Ventral lobes in untreated control and saline‑loaded SHRs.At 7 days after saline loading,there were
no obvious diﬀerences between the prostate ventral lobes of the untreated (A)and saline‑loaded SHRs
(B)when viewed and analyzed by image processing.H&E stain,x40.Both the control (C)and saline‑
loaded (D) SHRs had numerous proliferating epithelial cells that were positive for PCNA antibody(red). Bar = 50 μm. Apoptotic cells induced by caspase‑dependent or ‑independent pathways (green,arrow)were rarely present in the (E)control or (F)saline‑loaded SHRs. Bar = 10 μm Blue:nuclei.

No. 3, 2010107

Nakayama ･ Imamura ･ Ishizuka et al.

Fig. 2108

信州医誌 Vol. 58

α1‑adrenergic and angiotensin receptors
Table 2 Epithelial α1‑AR subtypes and AngiotensinII type 1 receptor in the ventral andlateral‑dorsal lobes of WKY rat
Lateral‑dorsal lobe

Ventral lobe
Untreated

Saline‑loaded

Untreated

Saline‑loaded

α1A adrenergic receptor (spots/μm )0.005±0.0012

0.004±0.0007

0.003±0.0008

0.003±0.0010

α1D adrenergic receptor (spots/μm )0.004±0.0007

0.004±0.0004

0.003±0.0002

0.003±0.0005

α1B adrenergic receptor (spots/μm )Angiotensin II type 1 receptor(spots/μm )0.005±0.0004

0.004±0.0003

0.005±0.0005

0.005±0.0009

0.004±0.0004

0.003±0.0006

0.004±0.0010

0.004±0.0008

signiﬁcantly lower in the ventral lobes compared to

duced a small degree of hyperplasia in the lateral‑the lateral‑dorsal lobes. In the saline‑loaded WKY

dorsal lobes, while not increasing the SBP and

rats,there were no diﬀerences between ventral andprostate weight.

lateral‑dorsal lobes (Table 2).

Expression of the three α1‑AR subtypes withinboth lobes of the saline‑loaded SHRs was

Discussion

signiﬁcantly higher than in the untreated controls.

The SBP of the SHRs reaches 180 to 200 mmHg
around 5‑6 weeks of age

and is promoted by

the administration of salt

.A high concentration

Theα1A‑AR plays a predominant role in mediatingsmooth muscle contraction activated by catecholamines in the prostate. The α1B‑AR medi-of salt increases the risk of death due to cerebrovas-

ates the blood pressure response to adrenergic stim-

cular accidents. Thus, we adopted a saline loading

ulationprotocol.However,the protocol did not signiﬁcantly

ation in the human prostateincrease the SBP further above the existing hyper-

results suggest that the increased α1‑AR subtypes,

tensive state. It also did not signiﬁcantly increase

especiallyα1D‑AR,might mediate the hyperplastic

prostate weight.

response induced by saline loading.

The ventral lobes within both SHR groups had
numerous PCNA ‑positive proliferating,and the α1D‑AR regulates cell prolifer. Therefore, ourThe expression of AT1 within both of the lobes ofcells

the saline‑loaded SHRs was also signiﬁcantly

compared to apoptotic cells.Yamashita et al.repor-higher than in the untreated controls. When an-

ted that the ventral lobe in SHRs is hyperplastic andgiotensin

predominantly composed of glandular epithelium .

cortex, aldosterone is released and increases blood

Our results also support these data even though ourpressure . In the prostate, angiotensin

saline‑loading conditions did not induce more ven-also binds to AT1 and promotes cell growth andtral lobe hyperplasia than in untreated SHRs. In

smooth muscle tone

contrast, the number of proliferating cells withinsin

the lateral‑dorsal lobes of the saline‑loaded SHRs

creased .Similarly,an increased level of angioten-

was signiﬁcantly higher than that of the untreatedsin

controls. Thus, our saline‑loading conditions in-in the prostates of SHRs . In our model, thepeptide binds to AT1 in the adrenal
peptide. In human BPH, angioten-

peptide is increased, whereas AT1 is depeptide is associated with a decrease of AT1

Fig. 2 α1‑AR subtypes and AT1 within the ventral lobes. There were fewer α1A ‑, α1D‑, and α1B‑ARs(A, C, and E, green, arrows) within the epithelial cells of the ventral lobes in the untreated control
SHRs than in the saline‑loaded ones (B,D,and F,green,arrows).Similarly,the expression of AT1(A,C,and E,red,arrowheads)within the epithelial cells of the ventral lobes of the control SHRs was also
lower than in the saline‑loaded ones (B, D, and F, red, arrowheads). Bars = 10 μm, Blue:nuclei.

No. 3, 2010109

Nakayama ･ Imamura ･ Ishizuka et al.

Fig. 3110

信州医誌 Vol. 58

α1‑adrenergic and angiotensin receptors

increase in AT1 suggested that the angiotensinthat our saline‑loading conditions for the SHRs

peptide of saline‑loaded SHRs might be decreased

increase the levels of receptors and peptides as-

in the prostate, though this must be determined insociated with LUTS.The combination of persistent

future studies. Thus, the absence of elevated SBP

hypertension and hyperglycemia or hyperlipidemia

might be due to a decrease in angiotensin

peptide.

is a well‑known metabolic syndrome. It increases

In each SHR group, the number of proliferating

the risk of developing not only cardiovascular dis-

cells and the expression of α1‑AR subtypes andease and diabetes, but also LUTS. In addition, theAT1 were diﬀerent between the ventral and lat-saline loading did not have any eﬀects on theeral‑dorsal lobes. In the untreated control SHRs,

expressions of α1‑AR subtypes and AT1 within thethe number of proliferating cells and the expression

prostates of WKY rats.Therefore,our SHR modelof epithelial α1A‑ARs in the ventral lobes were

will be useful in the investigation of LUTS induced

signiﬁcantly greater than those in the lateral‑dorsal

by this metabolic syndrome.

lobes. In contrast, the expression of epithelial AT1

The present study suggested that an AT1 blocker

in the control ventral lobes was signiﬁcantly lessmight be useful for the treatment of LUTS in BPH

than in the lateral‑dorsal lobes. The expression of

to suppress angiotensin Ⅱ activity of the prostate,

α1D‑ and α1B‑ARs was the same in the two lobes.

just as an α1‑AR blocker is the ﬁrst choice drug for

In the saline‑loaded SHRs,the number of prolifer-

LUTS in BPH to suppress α1‑AR activity of theating cells and the expression of epithelial α1A‑

prostate. Furthermore, control of hypertension and

ARs in the ventral lobes were also greater than in

sodium intake would help to prevent BPH progres-the lateral‑dorsal lobes.In contrast,the expression

sion.

of epithelial α1B‑ARs and AT1 in the ventral lobes

Conclusion

was signiﬁcantly less than in the lateral‑dorsal
lobes while the α1D‑ARs in saline‑loaded SHRs

Saline loading did not signiﬁcantly increase thewas the same in both lobes.The increased presence

SBP and the prostate weight of experimental rats.

of lateral‑dorsal α1B‑ARs due to saline loading

However,it did increase the number of proliferating

might have induced ischemia due to enhanced vascu-

cells within the lateral‑dorsal lobes of SHRs.

lar smooth muscle contraction in the SHR pros-

Furthermore, saline loading increased the expres-tates.

sion of prostate α1‑AR subtypes and AT1 in bothIn this study, we showed that saline loading in-

the ventral and lateral‑dorsal lobes of SHRs.

creased the expression ofα1‑AR subtypes and AT1

Changes of 1‑AR and AT1 in saline‑loaded SHRs

within the prostates of SHRs. Similarly, we previ-might be one of the mechanisms of LUTS associat-

ously showed that the loading of saline could

ed with BPH.

increase the expression of tachykinins,TRPV1,andP2X3 receptors within the urinary bladders of
SHRs .While the mechanism(s)of increased receptor expression are not yet established, it is clear

Fig. 3 Lateral‑dorsal lobes in untreated control and saline‑loaded SHRs. At 7 days after saline loading,there were no obvious diﬀerences between the prostate lateral‑dorsal lobes of the untreated (A)andsaline‑loaded SHRs (B) when viewed and analyzed by image processing. H&E stain, x40. (C) The
control SHRs had few PCNA‑positive epithelial cells (red). Bar = 50 μm. (D)In contrast,the saline‑
loaded SHRs had more PCNA‑positive epithelial cells than the controls (red).Bar =50μm.Apoptotic
cells induced by caspase‑dependent or ‑independent pathways (green, arrow) were rarely present inthe (E) untreated or (F) saline‑loaded SHRs. Bar = 20 μm, Blue:nuclei.

No. 3, 2010111

Nakayama ･ Imamura ･ Ishizuka et al.

Fig. 4112

信州医誌 Vol. 58

α1‑adrenergic and angiotensin receptors

Fig. 4 α1‑AR subtypes and AT1 within the lateral‑dorsal lobes. There were fewer α1A ‑, α1D‑,and
α1B‑AR (A,C,and E,green,arrows)within the epithelial cells of the untreated control lateral‑dorsal
lobes than in the saline‑loaded ones (B, D, and F, green, arrows). Similarly, the expression of AT1
within lateral‑dorsal lobe epithelium in the control SHRs (A, C, and E, red, arrowheads) was also
lower than in the saline‑loaded ones (B, D, and F, red, arrowheads). Bars = 10 μm, Blue:nuclei.

References
1

M aruenda J, Bhatnagar V, Lowenthal DT :Hypertension in the elderly with coexisting benign prostatic hyperplasia. Urology 53:7‑12;discussion 12‑3, 41‑2, 1999

2

Conrad CH, Brooks WW, Hayes JA, Sen S, Robinson KG, Bing OH : M yocardial ﬁbrosis and stiﬀness withhypertrophy and heart failure in the spontaneously hypertensive rat. Circulation 91:161‑170, 1995

3

Sevilla MA, Voces F, Carron R,Guerrero El,Ardanaz N,San Roman L,Arevalo M A,Montero M J :Amlodipine
decreases ﬁbrosis and cardiac hypertrophy in spontaneouslyhypertensive rats:Persistent eﬀects after withdrawal.
Life Sci 75:881‑891, 2004

4

Andersen ML, M artins RC, Alvarenga TA, Antunes IB, Papale LA, Tuﬁk S : Progesterone reduces erectile
dysfunction in sleep‑deprived spontaneously hypertensive rats. Reprod Biol Endocrinol 5:7, 2007

5

Ushiyama M,Morita T,Kuramochi T,Yagi S,Katayama S :Erectile dysfunction in hypertensive rats results from
impairment of the relaxation evoked by neurogenic carbon monoxide and nitric oxide.Hypertens Res 27:253‑261,
2004

6Wilkes N, White S, Stein P, Bernie J, Rajasekaran M : Phosphodiesterase‑5 inhibition synergizes rho‑kinaseantagonism and enhances erectile response in male hypertensive rats. Int J Impot Res 16:187‑194, 20047

Rodriguez‑Padilla M, Bellido C, Pinilla L, Aguilar E : Secretion of LH in spontaneously hypertensive rats. J
Endocrinol 113:255‑260, 1987

8

Jesik CJ, Holland JM, Lee C :An anatomic and histologic study of the rat prostate. Prostate 3:81‑97, 1982

9

Kojima Y, Sasaki S, Oda N, Koshimizu TA, Hayashi Y, Kiniwa M, Tsujimoto G, Kohori K :Prostate growth
inhibition by subtype‑selective alpha(1)‑adrenoceptor antagonist naftopidil in benign prostatic hyperplasia.
Prostate 69 :1521‑1528, 200910

Basso N,Terragno NA :History about the discovery of the renin‑angiotensin system.Hypertension 38:1246‑1249,
2001

11) Dinh DT, Frauman AG, Somers GR, Ohishi M , Zhou J, Caseley DJ, Johnston Cl, Fabiani M E : Evidence foractivation of the renin‑angiotensin system in the human prostate:Increased angiotensin

and reduced AT(1)receptor expression in benign prostatic hyperplasia. J Pathol 196:213‑219, 2002
12

Nassis L, Frauman AG, Ohishi M, Zhuo J, Casley DJ, Johnston Cl, Fabiani M E : Localization of angiotensin‑
converting enzyme in the human prostate:Pathological expression in benign prostatic hyperplasia.J Pathol 195:
571‑579, 2001

13

Imamura T,Ishizuka O,Zhong C,Ogawas T,Nakayama T,Kurizaki Y,Tanabe T,Nishizawa O,Andersson KE :An extract (THC‑002) of Ba‑Wei‑Die‑Huang‑Wan inhibits expression of tachykinins, and P2X3 and TRPV1
receptors,and inhibits ATP‑induced detrusor overactivity in spontaneously hypertensive rats.Neurourol Urodyn
28:529 ‑534, 200914

Kawabe K,Watanabe TX,Shiono K,Sokabe H :Inﬂuence on blood pressure of renal isografts between spontaneously hypertensive and normotensive rats, utilizing the F1 hybrids. Jpn Heart J 19 :886‑894, 1978

15

Rettig R :Does the kidney play a role in the aetiology of primary hypertension?Evidence from renal transplantation studies in rats and humans. J Hum Hypertens 7:177‑180, 199316

Toblli JE, Stella I, Inserra F, Ferder L, Zeller F, M azza ON : M orphological changes in cavernous tissue inspontaneously hypertensive rats. Am J Hypertens 13:686‑692, 2000

No. 3, 2010113

Nakayama ･ Imamura ･ Ishizuka et al.
17

de Wardener HE :The primary role of the kidney and salt intake in the aetiology of essential hypertension :Part
I. Clin Sci (Lond)79 :193‑200, 1990

18

Takata Y, Yamashita Y, Takishita S, Tsuchihashi T, Tomita Y, Kimura Y, Koga T,Fujishima M :Central andperipheral mechanisms of the enhanced hypertension following long‑term salt loading in spontaneously hypertensive rats. Jpn Circ J 52:1317‑1322, 1988

19

Yamashita M,Zhang X,Siraishi T,Uetsuki H,Kakehi Y :Determination of percent area density of epithelial andstromal components in development of prostatic hyperplasia in spontaneously hypertensive rats. Urology 61:
484‑489, 2003

20

Lepor H, Tang R, Kobayashi S, Shapiro E, Forray C, Watzel JM , Gluchowski C :Localization of the alpha 1a‑adrenoceptor in the human prostate. J Urol 154:2096‑2099, 1995

21

Walden PD,Durkin MM,Lepor H,Wetzel JM ,Gluchowski C,Gustafson EL :Localization of mRNA and receptor
binding sites for the alpha 1a‑adrenoceptor subtype in the rat,monkey and human urinary bladder and prostate.
J Urol 157:1032‑1038, 199722

Cavalli A, Lattion AL, Hummler E, Nenniger M , Pedrazzini JF, M ichel M C, Yang M , Lembo G, Vecchione C,
M ostardini M, Schmidt A, Beermann F, Cotecchia S :Decreased blood pressure response in mice deﬁcient of thealpha1b‑adrenergic receptor. Proc Natl Acad Sci U S A 94:11589 ‑11594, 1997

23

Vecchione C, Fratta L, Rizzoni D, Notte A, Poulet R, Porteri E, Frati G, GuelﬁD, Trimarco V, M ulvany M J,
Agabiti‑Rosei E, Trimarco B, Cotecchia S, Lembo G :Cardiovascular inﬂuences of alpha1b‑adrenergic receptor
defect in mice. Circulation 105:1700‑1707, 2002

24

Kojima Y, Sasaki S, Kubota Y, Hayase M, Hayashi Y, Shinoura H, Tsujimoto G, Kohri K : Expression ofalpha1‑adrenoceptor subtype mRNA as a predictor of the eﬃcacy of subtype selective alpha1‑adrenoceptor
antagonists in the management of benign prostatic hyperplasia. J Urol 179 :1040‑1046, 2008

25

Fabiani M E, Hawkes DJ, Frauman AG,Tikellis C,Johnston CI,Wilkinson‑Berka JL :Regulation of angiotensin
receptors in the prostate of the transgenic (mren‑2)27 rat :Eﬀect of angiotensin‑converting enzyme inhibition.
Int J Biochem Cell Biol 35:973‑983, 2003

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