Biology of the anococcygeus muscle

Gibson, Alan; McFadzean, Ian

doi:10.1016/s0074-7696(01)05001-x

Cited by 16 publications

(10 citation statements)

References 170 publications

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“…Anococcygeus and retractor penis muscles have been widely accepted as ideal smooth muscle models to study not only nitrergic neurotransmission but also other nonadrenergic noncholinergic neurotransmitters. 10,11 Since their vascular supply is not as rich as the corpus cavernosum, the involvement of eNOS is also limited. We have previously characterised the nitrergic neurotransmission in the anococcygeus muscle 12 and defective nitrergic neurotransmission has been well documented in diabetes models using this tissue.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

et al. 2004

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We compared the effects of a nitric oxide (NO)-releasing sildenafil (NCX-911), NO-independent soluble guanylate cyclase activator (BAY41-2272) and sildenafil on the anococcygeus muscle from streptozotocin-induced 16-weeks diabetic rats. NCX-911, BAY41-2272 and sildenafil reduced the phenylephrine-induced tone in the control group (EC 50 ¼ 1088.87165.0, 151.679.3 and 827.17167.3 nM, respectively). The potencies of NCX-911 and BAY41-2272 were not altered, but that of sildenafil was significantly reduced in the diabetic group. EC 50 values for NCX-911, BAY41-2272 and sildenafil in the diabetic group were 1765.97303.5, 209.7727.3 and 2842.27640.3 nM, respectively (Po0.05 for sildenafil). Nitrergic relaxation responses were significantly decreased in the diabetic group. The remaining nitrergic relaxation responses were potentiated by BAY41-2272 but not by sildenafil or NCX-911. These results confirm that endogenous NO derived from nitrergic nerves is significantly decreased in diabetes, and suggest that NO-releasing PDE5 inhibitors and NO-independent soluble guanylate cyclase activators could be more useful than PDE5 inhibitors in the treatment of ED in long-term diabetes.

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Section: Introductionmentioning

confidence: 99%

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

et al. 2004

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“…The rat ASM, representing different smooth muscles including the gastrointestinal tract, has been widely used to investigate the basic mechanisms underlying smooth muscle contraction-relaxation, and the nature of inhibitory neurotransmitters (Gibson and McFadzean, 2001). In the rat ASM, Ang II has been shown to cause contraction via AT 1 receptor activation, whereas AT 2 receptor leads to inhibition (de Godoy and de Oliveira, 2002).…”

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confidence: 99%

Angiotensin II-Induced Relaxation of Anococcygeus Smooth Muscle via Desensitization of AT₁Receptor, and Activation of AT₂Receptor Associated with Nitric-Oxide Synthase Pathway

Godoy

Oliveira²,

Rattan

2004

J Pharmacol Exp Ther

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We evaluated the role of receptor desensitization, activation of AT 2 receptors, and enzymatic degradation of angiotensin II (Ang II) by amino/neutral endopeptidases in rat anococcygeus smooth muscle (ASM) relaxation. Ang II (0.3 nM to 10 M) produced contractions (E max ϭ 21.50 Ϯ 5.73%) followed by passive relaxations (E max reduced to 9.08 Ϯ 2.55%). Contractions were inhibited (E max ϭ 13.67 Ϯ 2.03%) by losartan (0.1 M;,7-tetrahydro-1H-imidazo(4,5-c)pyridine-6-carboxylic acid] (0.1 M; AT 2 antagonist). Conversely, the passive relaxation was inhibited (E max ϭ 18.00 Ϯ 3.45%) by PD123,319 but not by losartan. Ang II (0.3 M to 100 M) produced initial contractions (E max ϭ 11.49 Ϯ 9.39%) followed by active relaxations [I max (maximum inhibition elicited by the agonist) ϭ 47.85 Ϯ 4.23%] on strips precontracted by bethanechol (100 M). A second administration of Ang II on the background of bethanechol (1 h later) resulted in stronger relaxations (I max ϭ 64.03 Ϯ 5.47%) without the initial contractions. N

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“…Adrenergic or cholinergic (muscarinic) agonists can also elicit contractile responses of the anococcygeus muscle by acting directly on either α‐adrenoceptors or muscarinic M 3 cholinoceptors present in the tissue. Appropriate combinations of pharmacological inhibitors or blockers can be used to confirm whether pre‐ or post‐junctional mechanisms are involved in eliciting either the contractile (noradrenergic) or relaxant (nitrergic) responses of the anococcygeus muscle 16,17 …”

Section: Investigating the Autonomic Effects Of Some Scorpion Venoms mentioning

confidence: 99%

Autonomic effects of some scorpion venoms and toxins

Gwee¹,

Nirthanan²,

Khoo³

et al. 2002

Clin Exp Pharma Physio

104

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5. Our studies confirmed that the rat anococcygeus muscle is an excellent nerve-smooth muscle preparation for investigating the effects of bioactive agents on noradrenergic and nitrergic transmission, as well as the direct agonist actions of these agents on post-synaptic ␣-adrenoceptors and M3 muscarinic cholinoceptors. Although many studies, including our own, have documented that scorpion venoms and toxins mediate their primary effects via a prejunctional mechanism that leads to the marked release of various autonomic neurotransmitters, our studies have shown that there are exceptions to this generally accepted phenomenon. In particular, we have provided firm evidence to show that the venoms from H. longimanus and H. spinifer do not have such a prejunctional site of action but, instead, the venoms mediate their autonomic effects through direct agonist actions on post-junctional muscarinic M3 cholinoceptors and ␣-adrenoceptors.

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Biology of the anococcygeus muscle

Cited by 16 publications

References 170 publications

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

Angiotensin II-Induced Relaxation of Anococcygeus Smooth Muscle via Desensitization of AT₁Receptor, and Activation of AT₂Receptor Associated with Nitric-Oxide Synthase Pathway

Autonomic effects of some scorpion venoms and toxins

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Biology of the anococcygeus muscle

Cited by 16 publications

References 170 publications

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

A comparative study of sildenafil, NCX-911 and BAY41-2272 on the anococcygeus muscle of diabetic rats

Angiotensin II-Induced Relaxation of Anococcygeus Smooth Muscle via Desensitization of AT1Receptor, and Activation of AT2Receptor Associated with Nitric-Oxide Synthase Pathway

Autonomic effects of some scorpion venoms and toxins

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Angiotensin II-Induced Relaxation of Anococcygeus Smooth Muscle via Desensitization of AT₁Receptor, and Activation of AT₂Receptor Associated with Nitric-Oxide Synthase Pathway