Detrusor muscle

Genitourinary—urinary urgency and difficulty with urination, caused by spasms of the ureter. Urinary urgency also may occur because of the action of the drugs on the detrusor muscle of the bladder. Some patients may experience difficulty voiding because of contraction of the bladder sphincter. 

Urinary fracf-d Natation of smooth muscles of the ureters and kidney pelvis, contraction of the detrusor muscle of the bladder... 

The expression of TRPVl in the bladder is, however, not restricted to afferent nerves urothelium, detrusor muscle and fibroblasts also express TRPVl in the human bladder [140]. The implication of these findings for intravesical vanilloid therapy is unclear [141], but the increase in TRPVl immunoreactivity in the urothelium in patients with neurogenic detrusor overactivity (that occurs in concert with increased TRPVl in bladder af-ferents) is a very intriguing finding [142]. In the male urogenital system, TRPVl is also present in testicles, prostate and scrotal skin [143], and it was postulated that TRPVl ligands may be beneficial in the treatment of benign prostatic hyperplasia [144]. 

O The lower urinary tract symptoms and signs of benign prostatic hyperplasia are due to static, dynamic, or detrusor factors. The static factor refers to anatomic obstruction of the bladder neck caused by an enlarged prostate gland. The dynamic factor refers to excessive stimulation of a-adrenergic receptors in the smooth muscle of the prostate, urethra, and bladder neck. The detrusor factor refers to irritability of hypertrophied detrusor muscle as a result of long-standing bladder outlet obstruction. 

Detrusor muscle Smooth muscle of the bladder body. When the detrusor muscle contracts, the bladder is emptied of urine. 

Bladder overactivity is known as urge UI (UUI) and is associated with increased urinary frequency and urgency, with or without urge incontinence. The detrusor muscle is overactive and contracts inappropriately during the filling phase. 

HT4 receptors are also present in the pig and human hearts, primarily located in the atrium [9]. Experiments showed that stimulation of these receptors can result in tachycardia and can trigger positive inotropic effects. Moreover, it has been demonstrated that the 5-HT4 receptor is present in the human detrusor muscle and facilitates a cholinergic mechanism which may lead to increased bladder contractions [10]. Finally, acute (but not repeated) stimulation of 5-HT4 receptors present on the human adrenal cortex has been reported to trigger the release of corticosterone and aldosterone [11]. 

Prostatic hypertrophy with impaired micturition loss of parasympathetic control of the detrusor muscle exacerbates difficulties in voiding urine. 

In patients with conditions characterized by involuntary bladder contractions, oxybutynin increases vesical capacity, diminishes frequency of uninhibited contractions of the detrusor muscle, and delays initial desire to void. Oxybutynin thus decreases urgency and the frequency of incontinent episodes and voluntary urination. 

The detrusor muscle (which contains (32-adrenoceptors) in the body of the urinary bladder is relaxed by epinephrine and isoproterenol. On the other hand, the trigone and sphincter (which contain aj-receptors) are contracted by norepinephrine and epinephrine this action inhibits the voiding of urine. 

Prominent effects within the digestive tract include stimulation of salivation and acid secretion, increased intestinal tone and peristaltic activity, and relaxation of most sphincters. Bronchoconstriction and stimulation of secretions are prominent effects in the respiratory system. Muscarinic agonists can also evoke secretion from nasopharyngeal glands. Urination is promoted by stimulation of the detrusor muscle of the bladder and is facilitated by relaxation of the trigone and external sphincter muscles. 

Urinary Urinary retention (relaxation of the detrusor muscle) relaxation of ureter... 

Muscarinic antagonists can cause urinary retention by blocking the excitatory effect of ACh on the detrusor muscle of the bladder. During urination, cholinergic input to this smooth muscle is activated by a stretch reflex. 

Mechanism of Action A cholinergic that acts directly at cholinergic receptors in the smooth muscle of the urinary bladder and GI tract. Increases detrusor muscle tone. Therapeutic Effect May initiate micturition and bladder emptying. Improves gastric and intestinal motility. 

Mechanism of Action A urinary antispasmodic t hat act s as a direct antagonist at muscarinic acetylcholine receptors in cholinergically innervated organs. Reduces tonus (elastictension) of smooth muscle in the bladder and slows parasympathetic contractions. Therapeutic Effect Decreases urinary bladder contractions, increases residual urine volume, and decreases detrusor muscle pressure. 

The detrusor muscle itself is of complex embryo-logical development, innervation, and function (Hun-... 

Urinary frequency and dysuria may be caused by high detrusor muscle tone or unstable neuromuscular function, but with good sensation and normal or excessive sphincter control. Extreme bladder sensitiv-... 

Daniel, E.E., Cowan, W., and Daniel, V.P. (1983) Structural bases for neural and myogenic control of human detrusor muscle. Can Physiol Pharmacol 61 1247-1273. 

Muscarinic agonists stimulate the detrusor muscle and relax the trigone and sphincter muscles of the bladder, thus promoting voiding. The function of M2 and M3 receptors in the urinary bladder appears to be the same as in intestinal... 

Yamaguchi O. Beta3-adrenoceptors in human detrusor muscle. Urology. 2002 59(suppl l) 25-29. 

Actions Bethanechol directly stimulates muscarinic receptors, causing increased intestinal motility and tone, and it also stimulates the detrusor muscles of the bladder while the trigone and sphincter are relaxed, causing expulsion of urine. 

After a 15-min equilibration period at zero volume, variations in intraluminal pressure are recorded in response to continuous infusion of saline at a rate of 2.8 ml/h at 37 °C for 30-40 min by means of a peristaltic pump connected to the polyethylene tubing inserted into the bladder. This infusion rate simulates the maximal hourly diuresis within the physiological range. In each preparation the infusion is continued until micturition occurs. Micturition is referred as the emission of several drops of fluid during a sustained phasic contraction of the detrusor muscle which is followed by return to zero or, in any case, to a value lower than that recorded just before micturition. 

Pietra et al. (1990) studied the effects of some antidepressants by the in vitro inhibition of carbachol-induced contractions of rat detrusor strip preparations. The detrusor muscle tissue (bladder dome) was cut in a semicircular direction and further dissected into strip preparations measuring approximately 2 x 20 mm. 

Anderson (1978) recommended the rabbit detrusor muscle as an unique in vitro smooth muscle preparation. Rabbit detrusor muscles are thin and devoid of underlying submucosal tissue with parallel fiber orientation. The tissue exhibits autorhythmicity, characteristic of most single unit type smooth muscle preparations and can be employed in either isometric or isotonic organ bath recording systems. 

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