Adenosine 5'-triphosphate and noradrenaline are excitatory cotransmitters to the fibromuscular stroma of the guinea pig prostate gland.
Immunohistochemical studies demonstrated abundant P2X(1)-receptor immunoreactivity colocalized with alpha-actin within the fibromuscular stroma of the guinea pig prostate. P2X(2)-, P2X(3)- and P2X(4)-receptor immunoreactivity was absent. alphabetamethylene Adenosine 5'-triphosphate (ATP) attenuated contractile responses to electrical field stimulation (50 V, 0.5 ms, 5-20 Hz) in the absence and presence of prazosin (0.3 microM). Responses to 1-2 Hz were unaffected. ARL 67156 (6-N, N-diethyl-beta-gamma-dibromomethylene-D-adenosine-5-triphosphate; 100 microM) enhanced contractile responses to electrical field stimulation (50 V, 0.5 ms, 10-20 Hz). Concentration-response curves to exogenously applied ATP analogues on unstimulated preparations elicited concentration-dependent suramin (100 microM)-sensitive contractions. The rank order of potency was: alphabetamethylene ATP>2methylthio ATP=betagammamethylene ATP>adenosine 5'-diphosphate (ADP)=ATP. Adenosine and adenosine 5'-monophosphate (AMP) did not produce contractile responses. These results demonstrate the presence of functional P2X(1)-receptors within the fibromuscular stroma of the guinea pig prostate and suggest a cotransmitter role for ATP with noradrenaline during high-frequency stimulation.
Buljubasich
Rosanda
R
Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
Ventura
Sabatino
S
D000199:Actins / Q000032:analysis; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006168:Guinea Pigs; D007150:Immunohistochemistry / Q000379:methods; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D011224:Prazosin / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D018048:Receptors, Purinergic P2 / Q000032:analysis; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D013498:Suramin / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
C092431:6-N,N-diethyl-beta,gamma-dibromomethylene-D-ATP; D000199:Actins; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058476:Receptors, Purinergic P2X2; D058848:Receptors, Purinergic P2X4; D013873:Thionucleotides; D013779:Tetrodotoxin; D013498:Suramin; D000244:Adenosine Diphosphate; D001285:Atropine; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D009638:Norepinephrine; D011224:Prazosin; C008501:2-methylthio-ATP