Effects of prostaglandins on vesicourethral smooth muscle of rabbit therapeutic implications

Khanna, Om P.; Barbieri, E; McMichael, Robert

doi:10.1016/0090-4295(78)90430-2

Cited by 33 publications

(15 citation statements)

References 12 publications

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“…In this study the rabbit circular ure thral smooth muscle strips showed a dose-dependent relaxation to PG Ei and E2 and a dose-dependent contrac tion to PG F2a, as with those seen in the canine urethra by Mutoh et al [6], Possible reasons for differences between our results and those of Khanna et al [3] are a directional difference of muscle strips (our strips: circular; Khannas': longitudinal), and age differences in the response to PGs [9]. PG Ei, E2 and F2a contracted the rabbit urinary blad der smooth muscle strips in the present study; results which were similar with previous reports [2][3][4][5][6][7][8][9]. In the present study, the responses to PG E1( E2 and F2a were found to be significantly greater in the bladder body than in the bladder base.…”

Section: Discussioncontrasting

confidence: 50%

“…Ghoneim et al [10] reported that PG E2 reduced the canine urethral resistance. Mutoh et al [6] noted that the female canine urethra was relaxed by PG Ei and E2 but was contracted by PG F2a-Khanna et al [3] showed that the rabbit ure-U rina ry bladder Fig. 4.…”

Section: Discussionmentioning

confidence: 99%

“…A large number of experiments [2][3][4][5][6][7][8][9] demonstrate that prostaglandin (PG) E|, E2 and F2a have contractile effects on the urinary blad % bladder dome(n) base(n) -lo g [PG] Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Prostaglandins E1 E2 and F2α on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

et al. 1994

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Prostaglandin (PG) E₁ E₂ and F_2α contracted smooth muscle strips from male adult rabbit urinary bladder. Contractile responses to each PG were significantly greater in urinary bladder body than in urinary bladder base. The magnitude of contractile response to each PG was F_2α > E₂ > E₁ in both of the bladder body and the bladder base. These contractions were almost completely eliminated by a calcium entry blocker, verapamil but not by atropine, phentolamine, propranolol or tetrodotoxin. PG E₁ and E₂ significantly relaxed the male rabbit urethral smooth muscle strips, whereas PG F_2α contracted the urethral smooth muscle strips. Cyclic adenosine monophosphate (cAMP) but not cyclic guanosine monophosphate (cGMP) increased significantly after administration of PG E₁ or E₂ in the urethral muscle strip. These results suggest that the regional differences in the magnitude of contractile responses to PG E₁, E₂ and F_2α between the bladder dome and the base and also suggest the contractile differences of PG E₁ and E₂ for the urinary bladder and the urethra; contractions for bladder and relaxations for urethra. These results also demonstrate that contractions induced by PG E₁, E₂ and F_2α in urinary bladder smooth muscles and by PG F_2α in urethral smooth muscles are mainly mediated by calcium influx and that relaxations induced by PG E₁ and E₂ in urethral smooth muscles are mediated by cAMP but not by cGMP.

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Section: Discussioncontrasting

confidence: 50%

Section: Discussionmentioning

confidence: 99%

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Effects of Prostaglandins E1 E2 and F2α on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

et al. 1994

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“…PGE 1 , PGE 2 , and PGF 2␣ all contract detrusor muscle, but in the urethra, PGE 1 and PGE 2 cause relaxation, whereas PGF 2␣ produces contraction (Andersson, 1993). This pattern of effects has been demonstrated in animal (Persson and Andersson, 1976;Khanna et al, 1978;Gotoh et al, 1986;Morita et al, 1994;Pinna et al, 1996), as well as human urethral smooth muscle (Andersson et al, 1978a). In women receiving PGE 2 intravesically or intraurethrally, a decrease in the maximum urethral pressure and a reduction of the closure pressure were found (Andersson et al, 1978a;Schussler, 1990).…”

Section: Pharmacology Of the Lower Urinary Tractmentioning

confidence: 81%

Pharmacology of the Lower Urinary Tract: Basis for Current and Future Treatments of Urinary Incontinence

Andersson

Wein²

2004

Pharmacol Rev

452

364

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“…slow, fatigueresistant fibres and fast-twitch, fatiguable fibres (Bazeed, Thuroff, Schmidt & Tanagho, 1982 (Kondo, Kobayashi, Takita & Narita, 1983;Mutoh, Ueda, Yano, Ikegami & Sakanishi, 1983), cat (Persson, 1976), pig (Klarskov et al 1983b) and human fetuses (Andersson, Persson, Alm, Kullander & Ulmsten, 1978). In contrast, in the rabbit it was reported that PGE2 had potent contractile effects on the bladder body, but its effects were minimal or absent on the bladder base or urethra (Khanna, Barbieri & McMichael, 1978), and in the cat urethra PGE2 contracted the longitudinal and relaxed the circular muscle layers (Abdel-Hakin, Massouna, Rioux, St-Pierre, Abdel-Rahman, Galeano & Elhilali, 1983). Thus, species difference is evident, and it should be borne in mind that even in the same tissue the drug action differs from circular to longitudinal muscle layers.…”

Section: Discussionmentioning

confidence: 99%

The neural and non‐neural mechanisms involved in urethral activity in rabbits.

Ito¹,

Kimoto²

1985

The Journal of Physiology

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SUMMARY1. The effects of electrical and chemical stimulation on the mechanical or electrical properties of the circular smooth muscle cells of the bladder neck, and proximal urethra of the male rabbit were investigated by means of micro-electrode, doublesucrose-gap and tension-recording methods.2. In the bladder neck, application of short current pulses (50 gs) produced an initial excitatory junction potential (e.j.p.) with a superimposed spike, followed by a late depolarization, and these electrical events evoked contraction. The initial e.j.p. was unaffected by guanethidine, phentolamine, methysergide or mepyramine, indicating the initial e.j.p. is not mediated by activation of adrenergic, tryptaminergic or histaminergic receptors. The late depolarization was enhanced by pre-treatment with neostigmine (10-7 M) and abolished by atropine (10-6 M).3. In the proximal urethra, electrical-field stimulation evoked phasic contraction which was followed by relaxation, associated with initial e.j.p.s, late depolarization and inhibitory junction potentials (i.j.p.s). Guanethidine (10-5 M) or phentolamine (10-6 M) reduced the size of the initial e.j.p. to 40-50 % of the control value and combined application of guanethidine and atropine further reduced the amplitude of the e.j.p. to 20-30 %. There was a parallel reduction in the mechanical response.The late depolarization was enhanced by neostigmine and abolished by atropine. The i.j.p. and muscle relaxation were not affected by propranolol, phentolamine, guanethidine or atropine.4. These results indicate that the proximal urethral smooth muscle cells are innervated by adrenergic and cholinergic excitatory, and by non-cholinergic nonadrenergic inhibitory nerve fibres.5. In the prostatic urethra, field stimulations also evoked twitch contractions with or without following phasic contraction and relaxation. The twitch contractions were abolished by d-tubocurarine (10-6 M), suggesting that they arise from striated muscle.6. Exogenously applied prostaglandin (PG) E1, PGE2 or PGF2. (> 10-1o M) evoked sustained increase in the muscle tone in the presence or absence of indomethacin, and enhanced the amplitude of muscle relaxation evoked by the field stimulation without affecting the resting membrane potential.* Authors' names are in alphabetical order.Y. ITO AND Y. KIMOTO 7. Indomethacin (10-6-10-5 M) gradually reduced the muscle tone of the proximal urethra with no change in the resting membrane potential. At the reduced muscle tone, electrical-field stimulation did not evoke muscle relaxation. Thus, the amplitude of muscle relaxation evoked by field stimulation was dependent on the level of muscle tone of the circular muscle strips.8. SC-19220 (a PG antagonist) also reduced the muscle tone of the proximal urethra, and consequently suppressed the amplitude of muscle relaxation evoked by field stimulation.9. These results indicate that endogenous PGs may play a physiological role in maintaining the muscle tone of the proximal urethral smooth muscle cells.

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Effects of prostaglandins on vesicourethral smooth muscle of rabbit therapeutic implications

Cited by 33 publications

References 12 publications

Effects of Prostaglandins E<sub>1</sub> E<sub>2</sub> and F<sub>2α</sub> on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

Effects of Prostaglandins E<sub>1</sub> E<sub>2</sub> and F<sub>2α</sub> on Contractility and cAMP and cGMP Contents in Lower Urinary Tract Smooth Muscle

Pharmacology of the Lower Urinary Tract: Basis for Current and Future Treatments of Urinary Incontinence

The neural and non‐neural mechanisms involved in urethral activity in rabbits.

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