Hyperosmolarity alters micturition: a comparison of urinary bladder motor activity in hyperosmolar and cyclophosphamide-induced models of overactive bladder

2010 ◽  
Vol 88 (9) ◽  
pp. 899-906 ◽  
Author(s):  
Kajetan Juszczak ◽  
Agata Ziomber ◽  
Marek Wyczółkowski ◽  
Piotr J. Thor
Keyword(s):  
Motor Activity ◽  
Isotonic Saline ◽  
Bladder Capacity ◽  
Physiological Model ◽  
Female Rats ◽  
Hypertonic Solution ◽  
Motility Index ◽  
Pressure Threshold ◽  
Experimental Tool ◽  
Saline Solutions

Hyperosmolar factors induce the neurogenic inflammatory response, leading to bladder overactivity (OAB). The aim of the study was to compare the bladder motor activity in a hyperosmolar and acute cyclophosphamide (CYP)-induced model of OAB. Furthermore, we set our sights on defining the most physiological model of OAB in experimental practice. Forty-two female rats were divided randomly into 5 groups. All animals underwent cystometry with the usage of isotonic saline or saline of increasing concentration. Acute chemical cystitis was induced by CYP to elicit OAB. The following cystometric parameters were analyzed: basal pressure, threshold pressure, micturition voiding pressure, intercontraction interval, compliance, functional bladder capacity, motility index, and detrusor overactivity index. CYP and hypertonic saline solutions induced OAB. Having been compared with CYP OAB, none of the rats infused with hypertonic solution exhibited macroscopic signs of bladder inflammation. The comparison of CYP and hyperosmolar models of OAB revealed that the greatest similarity existed between the 2080 mOsm/L OAB model and the acute CYP-induced model. We postulate that the 2080 mOsm/L model of OAB can be established as being a less invasive and more physiological model when compared with the CYP-induced OAB model. Additionally, it may also be a more reliable experimental tool for evaluating novel therapeutics for OAB as compared with CYP-induced models.

Effects of pH and osmolarity on aerosol-induced cough in normal volunteers

1988 ◽  
Vol 74 (4) ◽  
pp. 373-376 ◽  
Author(s):  
R. H. Lowry ◽  
A. M. Wood ◽  
T. W. Higenbottam
Keyword(s):  
Citric Acid ◽  
Sodium Citrate ◽  
Isotonic Saline ◽  
Chloride Concentration ◽  
Hypertonic Solution ◽  
Ionic Content ◽  
Normal Volunteers ◽  
Cough Frequency ◽  
Saline Solutions

1. The chemosensitivity of cough receptors stimulated by inhalation of aqueous aerosols was evaluated in 21 normal volunteers in three experiments. 2. The pH of isotonic saline was altered using small amounts of phosphate or glycine buffers to produce solutions with a pH range of 2.6–10.0. These solutions were nebulized ultrasonically and breathed for 1 min periods by seven subjects in random order and on separate days. Cough frequency during each 1 min inhalation was recorded. Only the two solutions of extreme pH (2.6 and 10.0) caused cough. 3. The effect of altering the osmolarity of the inhaled aerosol on cough was assessed using d-glucose over a range of 77–1232 mosmol/l. Saline solutions over the same range of osmolarity were also tested. The pH of d-glucose was raised to match that of saline by adding small amounts of sodium hydroxide. All solutions were nebulized and inhaled by seven subjects as described above for 1 min periods during which cough frequency was recorded. Forced expired volume in 1 s was recorded after each inhalation and did not alter in any subject by more than 10%. Subjects coughed when inhaling all the d-glucose solutions over the whole range of osmolarity. Cough occurred with saline solutions only at low chloride concentration and at the highest concentration. 4. In order to clarify whether the response to hypertonic saline was due to the high ionic content of the solutions or to its hypertonicity, two other solutions were tested. These were an isotonic and a hypertonic mixture of d-glucose and saline, containing ‘normal’ (150 mmol/l) ionic content. Cough occurred with the hypertonic solution but not with the isotonic solution, suggesting that hypertonicity does stimulate cough. 5. The mechanism of cough induction by citric acid was studied. An aerosol of 0.68% citric acid in saline was compared with sodium citrate, both with and without chloride, with d-glucose and with water in seven subjects. Cough occurred in response to all aerosols except sodium citrate in saline solvent. Additive effects of low pH and lack of chloride, and not the citrate ion, are responsible for the irritant properties of citric acid. 6. The chemosensitivity of the cough reflex induced by inhaled aerosols mirrors that already described in vivo for laryngeal rapidly adapting receptors.

The role of the peripheral cannabinoid system in the pathogenesis of detrusor overactivity evoked by increased intravesical osmolarity in rats

2015 ◽  
Vol 93 (8) ◽  
pp. 721-726 ◽  
Author(s):  
Kajetan Juszczak ◽  
Piotr Maciukiewicz
Keyword(s):  
Urinary Bladder ◽  
Detrusor Overactivity ◽  
Cannabinoid Receptors ◽  
Bladder Capacity ◽  
Pressure Profile ◽  
Intravesical Instillation ◽  
Motility Index ◽  
Urinary Bladder Dysfunction ◽  
Cb2 Receptors ◽  
Cb1 And Cb2 Receptors

The cannabinoid receptors CB1 and CB2 are localized in the urinary bladder and play a role in the regulation of its function. We investigated the pathomechanisms through which hyperosmolarity induces detrusor overactivity (DO). We compared urinary bladder activity in response to blockade of CB1 and CB2 receptors using AM281 and AM630, respectively, in normal rats and after hyperosmolar stimulation. Experiments were performed on 44 rats. DO was induced by intravesical instillation of hyperosmolar saline. Surgical procedures and cystometry were performed under urethane anaesthesia. The measurements represent the average of 5 bladder micturition cycles. We analysed basal, threshold, and micturition voiding pressure; intercontraction interval; compliance; functional bladder capacity; motility index; and detrusor overactivity index. The blockage of CB1 and CB2 receptors diminished the severity of hyperosmolar-induced DO. In comparison with naïve animals the increased frequency of voiding with no significant effect on intravesical voiding pressure profile was observed as a result of the blockage of CB1 and CB2 receptors. These results demonstrate that hyperosmolar-induced DO is mediated by CB1 and CB2 receptors. Therefore, the cannabinoid pathway could potentially be a target for the treatment of urinary bladder dysfunction.

Intestinal motility during acute Yersinia enterocolitica enteritis in rabbits

1989 ◽  
Vol 67 (6) ◽  
pp. 553-560 ◽  
Author(s):  
R. B. Scott ◽  
D. G. Gall ◽  
S. C. Diamant
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Motor Activity ◽  
Yersinia Enterocolitica ◽  
Phase Iii ◽  
Intestinal Lumen ◽  
Fecal Excretion ◽  
Cycle Period ◽  
Motility Index ◽  
And Control

To determine if Yersinia enterocolitica (YE) enteritis is associated with an alteration of intestinal myoelectric and motor activity, and with an increased rate of aboral transit, New Zealand white rabbits (500–900 g) were surgically prepared with ileal bipolar electrodes and a manometry catheter adjacent to the distal electrode. One week later animals were inoculated with 1010 organisms of YE in 10 mL NaHCO3 (infected group) or 10 mL NaHCO3 (sham-infected pair-fed and control groups). Daily food intake, weight gain, YE excretion, and stool pattern were noted. Intestinal myoelectric and motor activity over a 6- to 8- h period before and 3, 6, and 14 days after inoculation was compared in infected (I), pair-fed (PF), and control (C) groups. Intestinal transit was evaluated in I and C animals on days 3 and 6 after inoculation by measuring the distribution in the intestinal lumen of 51Cr 20 min after it was instilled directly into the jejunum. Infected animals exhibited diarrhea, fecal excretion of YE, and significantly decreased food intake, weight gain, and survival (11.4 ± 0.6 days). Infection was associated with a significant (p < 0.05) decrease in both the cycle period of the migrating myoelectric complex (MMC) and the total number of single, paired, and (or) clustered contractions per MMC, and a significant (p < 0.001) increase in duration of phase III of the MMC. There was no change in intestinal slow wave frequency (19 cycles/min), motility index per MMC, or the percentage of contractions that propagated in an orad (7%) or aboral (69%) direction or that appeared stationary (25%). The changes in myoelectric and motor activity were specific for YE infection (not related to decreased food intake and weight gain) and were associated with a significantly increased rate of aboral transit. Thus, the inflammatory enteritis induced by YE is associated with alterations of intestinal myoelectric and motor activity, and an increased rate of aboral transit.Key words: Yersinia enterocolitica, infection, intestine, motility, transit.

GABAergic contribution to rat bladder hyperactivity after middle cerebral artery occlusion

2000 ◽  
Vol 279 (4) ◽  
pp. R1230-R1238 ◽  
Author(s):  
Sayoko Kanie ◽  
Osamu Yokoyama ◽  
Kazuto Komatsu ◽  
Koichi Kodama ◽  
Satoshi Yotsuyanagi ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Receptor Agonist ◽  
Bladder Capacity ◽  
Artery Occlusion ◽  
Female Rats ◽  
Left Middle Cerebral Artery ◽  
Urethral Pressure ◽  
Cerebral Artery Occlusion

To evaluate the influences of γ-aminobutyric acid (GABA) mechanisms on bladder hyperactivity after left middle cerebral artery occlusion, cystometric recordings were obtained from unanesthetized female rats. Intracerebroventricular administration of both muscimol (GABAA receptor agonist; 0.1–10 nmol) and baclofen (GABAB receptor agonist; 0.1–3 nmol) produced dose-dependent inhibitions of micturition with increases in bladder capacity (BC). The effects of high doses (1–10 nmol) were similar in sham-operated (SO) and cerebral-infarcted (CI) rats. However, lower doses of muscimol (0.1 or 0.3 nmol) and baclofen (0.1 nmol) reduced BC in CI rats. After bicuculline (GABAA receptor antagonist; 1 or 3 nmol) administration, BC in both SO and CI rats first decreased and subsequently increased. An increase in urethral pressure was observed after administration of bicuculline (3 nmol) but not with either muscimol or baclofen. Infarct volumes in muscimol-, bicuculline-, or baclofen-treated rats were not significantly different from those of vehicle-treated rats. These results suggest that GABAergic mechanisms inhibit the micturition reflex at the supraspinal level but that this can change as a result of CI.

Renal concentrating ability in the uninephrectomized rat

1977 ◽  
Vol 233 (5) ◽  
pp. F428-F437
Author(s):  
E. Sachtjen ◽  
L. Rabinowitz ◽  
P. E. Binkerd
Keyword(s):  
Glomerular Filtration ◽  
Excretion Rate ◽  
Isotonic Saline ◽  
Urine Osmolality ◽  
Female Rats ◽  
Sham Operation ◽  
Urine Collection ◽  
Acute Elevation ◽  
The Mean ◽  
Solute Excretion

To investigate the effects of uninephrectomy on renal concentrating ability, studies were performed on unanesthetized rats 5-11 days after uninephrectomy (UN) or a sham operation (SO). Female rats were deprived of water for 27 h prior to the infusion of inulin and para-aminohippurate and urine collection. They were also preconditioned to being handled and to the experimental locale. During a nondiuretic state urine osmolality was the same for all UN and SO groups (mean about 1,700 micro osmol/g H2O), whereas the mean solute excretion rate (micro osmol/min per kg body wt per kidney) was 74 in the UN and 35 in the SO rats. When SO rats were infused with mannitol or isotonic saline to increase their solute excretion rate per kidney to the level of the UN rats, urine osmolality dropped 200-1,000 micro osmol/g H2O; when urea was infused, urine osmolality did not drop. Thus, after uninephrectomy and a consequent doubling of the solute excretion rate per kidney, renal concentrating ability was higher than predicted on the basis of a comparable but acute elevation of the solute excretion rate. The glomerular filtration rate was about 17 ml/min per kg body wt in the SO rats and was 1.2 times greater (on a per kidney basis) in the UN rats. These exceptionally high glomerular filtration rats are attributed to preexperimental conditioning of the rats and the absence of stress during urine collection.

Effects of intraduodenal glucose infusion on gastric myoelectrical activity and antropyloroduodenal motility

1998 ◽  
Vol 274 (6) ◽  
pp. G1038-G1044 ◽  
Author(s):  
M. A. M. T. Verhagen ◽  
M. Samsom ◽  
A. J. P. M. Smout
Keyword(s):  
Motor Activity ◽  
Dominant Frequency ◽  
Glucose Infusion ◽  
Pressure Waves ◽  
Gastric Myoelectrical Activity ◽  
Myoelectrical Activity ◽  
Motility Index ◽  
Antral Motility ◽  
Pyloric Tone ◽  
Pyloric Motility

Intraduodenal nutrient infusions cause an inhibition of antral motility and an increase in pyloric motility. The involvement of gastric myoelectrical activity in this intestinogastric feedback was studied. Electrogastrography and antropyloroduodenal manometry were performed in 10 healthy volunteers. The effects of 20-min infusions of 25% glucose (4 kcal/min) and saline were compared. Intraduodenal glucose infusions caused a decrease in the power of the dominant frequency in the electrogastrogram ( P = 0.028), but the frequency itself remained unchanged. The total number of dysrhythmias increased ( P = 0.035). An inhibition of antral motor activity ( P = 0.001), an increase in the number of isolated pyloric pressure waves ( P = 0.027), and an increase in basal pyloric tone ( P = 0.001) were simultaneously recorded. The change in power during glucose infusion correlated positively with the change in the antral motility index ( rs= 0.50, P = 0.001). It is concluded that inhibition of gastric myoelectrical activity is one of the mechanisms underlying an inhibition of motor activity in the gastric antrum.

Hypothalamic thermal stimulation modulates vasopressin release in hyperosmotically stimulated rabbits

1994 ◽  
Vol 267 (4) ◽  
pp. R1089-R1097 ◽  
Author(s):  
R. Keil ◽  
R. Gerstberger ◽  
E. Simon
Keyword(s):  
Isotonic Saline ◽  
Plasma Osmolality ◽  
Significant Rise ◽  
Hypertonic Solution ◽  
Temperature Plasma ◽  
Evaporative Water ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Hypothalamic Control ◽  
Hypertonic Stimulation

Under thermoneutral conditions conscious rabbits received systemic infusions of NaCl as hypertonic solution (90 mueq.min-1.kg body wt-1), which raised their plasma osmolality from 283 to 312 mosmol/kgH2O. Rabbits receiving isotonic saline served as controls. Hypertonic stimulation induced a 60% reduction of both respiratory frequency and evaporative water loss. Rectal temperature rose by 0.4 degrees C despite enhanced peripheral vasodilation as indicated by increased ear skin temperature. Plasma vasopressin (AVP), aldosterone (ALDO), and corticosterone (COR) were significantly elevated from 6 to 16 pg/ml, 90 to 180 pg/ml, and 17 to 40 ng/ml, respectively. To elucidate the importance of central temperature for AVP and adrenal corticosteroid release, hypothalamic thermal stimulations (20 min) were superimposed during established iso- and hyperosmotic steady-state conditions. Different from isosmotic controls, hyperosmotic animals responded to hypothalamic cooling (37 degrees C) with a significant decrease in plasma AVP from 16 to 13 pg/ml and to hypothalamic warming (41 degrees C) with a significant rise from 16 to 19 pg/ml. A weak temperature effect on COR release was also disclosed, especially of hypothalamic cooling, which significantly lowered plasma COR from 42 to 34 ng/ml. These results provide evidence for positive local temperature coefficients of hypothalamic control of AVP release and suggest a similar property also for the control of COR release by the hypothalamo-adenohypophysial axis.

Abdominal muscle activity during voiding in female rats with normal or irritated bladder

2006 ◽  
Vol 290 (5) ◽  
pp. R1436-R1445 ◽  
Author(s):  
Yolanda Cruz ◽  
John W. Downie
Keyword(s):  
Acetic Acid ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Female Rats ◽  
Emg Activity ◽  
Contraction Duration ◽  
Pressure Threshold ◽  
Acid Effect ◽  
Bladder Contraction ◽  
Sensory Pathway

The aims of the present study were to determine in female rats whether abdominal muscle discharges during normal voiding and to describe the effect of bladder irritation on this visceromotor activity. The sensory pathway of this reflex was also determined. Electromyograms (EMGs) indicated that in awake rats, the abdominal muscle was consistently activated during spontaneous voiding and during voiding induced by saline infusion. Similarly, in anesthetized animals, the muscle discharged during urine expulsion. The abdominal EMG activity was not abolished by hypogastric (Hgnx) or sensory pudendal neurectomy (SPdnx). SPdnx dramatically decreased the intercontraction interval and voided volume. Acetic acid infusion reduced the intercontraction interval and increased bladder contraction duration. It also reduced the pressure threshold for evoking the abdominal EMG response and increased the EMG duration and amplitude. Although SPdnx and Hgnx modified some urodynamic parameters, they did not reverse the acetic acid effect on EMG activity. Thus the afferents activating the visceromotor reflex during normal voiding and the increased reflex in response to acetic acid are probably both carried by the pelvic nerve. Abdominal muscle activity induced by bladder distension has been considered to be a pain marker. However, we conclude that in female rats, the abdominal muscle is reflexively activated during physiological urine expulsion. On the other hand, bladder irritation is marked by an exaggeration of this abdominal visceromotor reflex.

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