Guinea pig as an animal model for the study of urinary bladder function in the normal and obstructed state

The urinary bladder (UB) serves as a storage and elimination organ for urine. UB dysfunction can cause multiple symptoms of failure to store urine or empty the bladder, e.g., incontinence, frequent urination, and urinary retention. Treatment of these symptoms requires knowledge on bladder function, which involves physiology, pathology, and even psychology. There is no ideal animal model for the study of UB function to understand and treat associated disorders, as the complexity in humans differs from that of other species. However, several animal models are available to study a variety of other bladder disorders. Such models include animals from rodents to nonhuman primates, such as mice, rats, rabbits, felines, canines, pigs, and mini pigs. For incontinence, vaginal distention might mimic birth trauma and can be measured based on leak point pressure. Using peripheral and central models, inflammation, bladder outlet obstruction, and genetic models facilitated the study of overactive bladder. However, the larger the animal model, the more difficult the study is, due to the associated animal ethics issues, laboratory facility, and budget. This review aims at facilitating adapted animal models to study bladder function according to facility, priority, and disease.

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Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00656.2010 ◽

2011 ◽

Vol 301 (2) ◽

pp. R351-R362 ◽

Cited By ~ 23

Author(s):

Thomas J. Heppner ◽

Jeffrey J. Layne ◽

Jessica M. Pearson ◽

Hagop Sarkissian ◽

Mark T. Nelson

Keyword(s):

Smooth Muscle ◽

Urinary Bladder ◽

Guinea Pig ◽

Purinergic Receptor ◽

Bk Channels ◽

Bk Channel ◽

Cholinergic Receptors ◽

Bladder Function ◽

Muscularis Mucosae ◽

Maximal Force

The muscularis mucosae, a type of smooth muscle located between the urothelium and the urinary bladder detrusor, has been described, although its properties and role in bladder function have not been characterized. Here, using mucosal tissue strips isolated from guinea pig urinary bladders, we identified spontaneous phasic contractions (SPCs) that appear to originate in the muscularis mucosae. This smooth muscle layer exhibited Ca2+ waves and flashes, but localized Ca2+ events (Ca2+ sparks, purinergic receptor-mediated transients) were not detected. Ca2+ flashes, often in bursts, occurred with a frequency (∼5.7/min) similar to that of SPCs (∼4/min), suggesting that SPCs are triggered by bursts of Ca2+ flashes. The force generated by a single mucosal SPC represented the maximal force of the strip, whereas a single detrusor SPC was ∼3% of maximal force of the detrusor strip. Electrical field stimulation (0.5–50 Hz) evoked force transients in isolated detrusor and mucosal strips. Inhibition of cholinergic receptors significantly decreased force in detrusor and mucosal strips (at higher frequencies). Concurrent inhibition of purinergic and cholinergic receptors nearly abolished evoked responses in detrusor and mucosae. Mucosal SPCs were unaffected by blocking small-conductance Ca2+-activated K+ (SK) channels with apamin and were unchanged by blocking large-conductance Ca2+-activated K+ (BK) channels with iberiotoxin (IbTX), indicating that SK and BK channels play a much smaller role in regulating muscularis mucosae SPCs than they do in regulating detrusor SPCs. Consistent with this, BK channel current density in myocytes from muscularis mucosae was ∼20% of that in detrusor myocytes. These findings indicate that the muscularis mucosae in guinea pig represents a second smooth muscle compartment that is physiologically and pharmacologically distinct from the detrusor and may contribute to the overall contractile properties of the urinary bladder.

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Effects of Sensitization on Female Guinea Pig Urinary Bladder Function: In Vivo and in Vitro Studies

The Journal of Urology ◽

10.1016/s0022-5347(17)37823-0 ◽

1991 ◽

Vol 146 (2 Part 1) ◽

pp. 454-457 ◽

Cited By ~ 21

Author(s):

Young Soo Kim ◽

Penelope A. Longhurst ◽

Alan J. Wein ◽

Robert M. Levin

Keyword(s):

Urinary Bladder ◽

Guinea Pig ◽

In Vitro Studies ◽

Bladder Function

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TRP Channel Agonists Activate Different Afferent Neuromodulatory Mechanisms in Guinea Pig Urinary Bladder

Frontiers in Physiology ◽

10.3389/fphys.2021.692719 ◽

2021 ◽

Vol 12 ◽

Author(s):

Stephanie L. Daugherty ◽

Jonathan M. Beckel ◽

Kyoungeun A. Kim ◽

Bruce A. Freeman ◽

Jiaxin Liu ◽

...

Keyword(s):

Urinary Bladder ◽

Guinea Pig ◽

Trp Channels ◽

Allyl Isothiocyanate ◽

Inhibitory Effect ◽

Bladder Function ◽

Trpc Channels ◽

Afferent Nerves ◽

Bladder Activity ◽

Trpv1 Antagonist

Activation of TRP channels expressed in urinary bladder afferent nerves and urothelium releases neurotransmitters that influence bladder function. Experiments were undertaken to examine the mechanisms underlying effects of TRPA1 (allyl isothiocyanate, AITC), TRPV1 (capsaicin, CAPS), and TRPC (oleoyl-2-acetyl-sn-glycerol, OAG) agonists on guinea pig bladder activity. Effects of these agonists were compared with effects of nitro-oleic acid (OA-NO2), an electrophilic nitro-fatty acid, known to activate TRPV1, TRPA1 or TRPC channels in sensory neurons. AITC (100 μM) increased (231%) area of spontaneous bladder contractions (SBCs) an effect reduced by a TRPA1 antagonist (HC3-03001, HC3, 10 μM) and reversed to inhibition by indomethacin (INDO, 500 nM) a cyclooxygenase inhibitor. The post-INDO inhibitory effect of AITC was mimicked (39% depression) by calcitonin gene-related peptide (CGRP, 100 nM) and blocked by a CGRP antagonist (BIBN, 25 μM). CAPS (1 μM) suppressed SBCs by 30% in 81% of strips, an effect blocked by a TRPV1 antagonist (diarylpiperazine, 1 μM) or BIBN. SBCs were suppressed by OA-NO2 (30 μM, 21% in 77% of strips) or by OAG (50 μM, 30%) an effect blocked by BIBN. OA-NO2 effects were not altered by HC3 or diarylpiperazine. OA-NO2 also induced excitation in 23% of bladder strips. These observations raise the possibility that guinea pig bladder is innervated by at least two types of afferent nerves: [1] Type A express TRPA1 receptors that induce the release of prostaglandins and excite the detrusor, [2] Type B express TRPV1, TRPA1 and TRPC receptors and release CGRP that inhibits the detrusor.

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