Molecular and pharmacological detection of dopaminergic receptors in the human male urinary tract.
OBJECTIVE
Evidence indicates that dopamine (DA) and DA receptors play a role in the central nervous system (CNS) control of micturition; however, while the central DAergic role in the micturition physiology has been extensively investigated, the expression and the function of DA receptors in the urinary tract are still under investigation. Here, we studied the distribution of DA receptor subtypes in different parts of the human male urinary tract.


METHODS
Fragments were collected from 34 men. The mRNAs encoding DA receptors were assessed by RT-PCR, followed by densitometric analysis. Adenylyl cyclase (AC) activity was evaluated using a commercially available RIA kit. Statistical analysis was carried out using one-way ANOVA, with the Bonferroni's post hoc test.


RESULTS
Results obtained indicated that RT-PCR products of D(1), D(4), and D(5) subtypes were obtained in each part studied, while no signal was observed for the D(2) and D(3) receptor subtypes. The pharmacological characterization demonstrated that the expressed DA receptors were linked to AC.


CONCLUSIONS
DA receptors were expressed throughout the human male urinary tract, from the ureter to the prostatic urethra. In particular, we observed a distinctive DA receptor subtype distribution, with evidence of the presence of mRNA encoding both subtypes of the D(1)-like DA receptor family (D(1) and D(5)), while the D(4) receptors were the only expressed subtype of the D(2)-like family. These results suggested that DAergic drugs used for the treatment of a number of diseases may influence the micturition physiology not only in the CNS, but at the peripheral level as well.
Arrighi
Nicola
N
Division of Urology, University of Brescia Medical School, P.le Spedali Civili 1, Brescia, Italy.
Bodei
Serena
S
Zani
Danilo
D
Simeone
Claudio
C
Fiorentini
Chiara
C
Missale
Cristina
C
Milanese
Giulio
G
Dellabella
Marco
M
Muzzonigro
Giovanni
G
Cunico
Sergio Cosciani
SC
Spano
PierFranco
P
Sigala
Sandra
S
D000262:Adenylyl Cyclases / Q000378:metabolism; D000368:Aged; D000242:Cyclic AMP / Q000502:physiology; D015259:Dopamine Agents / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011954:Receptors, Dopamine / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D017447:Receptors, Dopamine D1 / Q000187:drug effects / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014513:Ureter / Q000187:drug effects / Q000502:physiology; D014521:Urethra / Q000187:drug effects / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology; D014551:Urinary Tract / Q000187:drug effects*; D014553:Urinary Tract Physiological Phenomena / Q000187:drug effects*
D015259:Dopamine Agents; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D000242:Cyclic AMP; D000262:Adenylyl Cyclases