title: Prejunctional facilitatory effect of a thiol-alkylating agent N-Ethylmaleimide on neurogenic contractions in rat prostate smooth muscle.
abstract: OBJECTIVE
  The effect of a non-specific thiol-alkylating agent N-ethylmaleimide (NEM) was studied on neurogenic contractile mechanisms in rat ventral prostate gland.
  
  
  METHODS
  Male Wistar albino rats were used. The rats were killed by cervical dislocation under sevoflurane anesthesia and ventral prostate gland was removed. Two preparations were obtained from each lobe. Neurally evoked isometric contractions were induced using trains of electrical field stimulation (EFS; 0.5, 1, 4, or 8 Hz). The effect of NEM on the contractions to EFS was examined in the absence or presence of adrenergic and/or purinergic antagonists.
  
  
  RESULTS
  NEM enhanced the EFS-evoked contractions without altering the basal tone. These effects were significantly suppressed by an α(1) -adrenergic receptor antagonist (prazosin), a P2-purinergic antagonist (suramin), a specific P2X-receptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS), an ATP analog (α,β-methylene ATP), or a calcium channel blocker (verapamil). This facilitating effect of NEM did not occur following the administration of L-cysteine or glutathione which saturated NEM with excess thiols. However, a thiol-oxidant diamide failed to affect the contractions to EFS. An adrenergic neuron blocker (guanethidine) completely suppressed the responses to NEM. On the other hand, an α(2) -adrenergic receptor blocker (yohimbine), a nitric oxide synthase inhibitor (N(ω) -nitro-L-arginine) or a cholinergic muscarinic receptor antagonist (atropine) did not significantly affect the facilitatory response of NEM.
  
  
  CONCLUSIONS
  These findings suggest that NEM has a prejunctional facilitatory action on the adrenergic nerves in rat prostate tissue to enhance release of transmitters, noradrenaline, and ATP. NEM sensitive proteins involved in transmitter release mechanisms can play a role in this effect.
authors.affiliation: Adana Health School, Adana, Turkey.
authors.forename: Hacer S G
authors.initials: HS
authors.lastname: Büyüknacar
authors.forename: Nadire
authors.initials: N
authors.lastname: Eser
authors.forename: Cemil
authors.initials: C
authors.lastname: Göçmen
authors.forename: William C
authors.initials: WC
authors.lastname: de Groat
authors.forename: Eda K
authors.initials: EK
authors.lastname: Kumcu
authors.forename: Peyman U
authors.initials: PU
authors.lastname: Ertuğ
authors.forename: Serpil
authors.initials: S
authors.lastname: Onder
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology*; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D019335:Nitroarginine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013498:Suramin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D018727:Muscarinic Antagonists; D019335:Nitroarginine; D013498:Suramin; D001285:Atropine; D014700:Verapamil; D005033:Ethylmaleimide; D011224:Prazosin