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Abstract

Regional and age specific differences are observed in the sodium nitroprusside induced relaxation responses in the urinary tract. To clarify these differences, guanylyl cyclase activity is assayed in particulate and soluble fractions from the ureter, bladder dome, and urethra of young (11-18 days), adult (90-100 days), and old adult (2-3 years) guinea pigs. The rank order of soluble guanylyl cyclase activities is urethra = ureter > bladder dome with the largest decreases with aging occurring in the bladder. Atrial natriuretic factor (10(7) M) increases particulate guanylyl cyclase activity in the three tissues at all ages tested, with the activity being highest in the ureter. ATP (0.5 mM) activates particulate guanylyl cyclase in the ureter, bladder and urethra of old adult guinea pigs, and enhances atrial natriuretic factor induced activation of particulate guanylyl cyclase in all tissues and at all ages tested. The higher levels of soluble guanylyl cyclase activity in the urethra and ureter compared to the bladder parallel sodium nitroprusside induced relaxation in these tissues.

The aging bladder insights from animal models

“…The purinergic component of the efferent transmission has been shown to be upregulated in conditions associated with overactive bladder [49] , including aging [50] , [51] . It is believed that increased of ATP release from parasympathetic nerves with aging [51] may result in decrease expression of P2X1 mRNA expression in the smooth muscle (in human tissue) [52] .…”

Translational Research and Functional Changes in Voiding Function in Older Adults

“…These include C57Bl6 mice (male, female 22–25 month old) 42–44 , the senescent-accelerated prone mice (SAMP8; male, female, 36–38 week old) 45 , Fisher 344 rats (male 22–24 month old) 46, 47 , Fischer/Brown Norway rats (male 28–30 month old) 48 , Wistar rats (male or female 22–37 month old) 49–51 , Fisher 344 rats (female 24 month old) 52 , Sprague Dawley (SD) rats (male 18–24 month old) 5354 . Other species included dogs 55, 56 and guinea pigs 57–61 . As pointed out previously, the relation between aging per se and external influences on the detrusor from diseases in the nervous system, in the vascular supply, and in the lower urinary tract smooth muscles, is poorly understood in humans 62–64 .…”