Functional assessment of rat urinary bladder with Fourier impedance cystometry

Objective. Functional assessment of urinary bladder in health and disease is made by different complex, modern equipment dependent methods according to bladder blood circulation and neural activity. Present report is dedicated to novel method of simultaneous assessment of circulation and neural activity in urinary bladder based on Fourier analysis of its impedance variations. Materials and methods. A novel method of simultaneous assessment of circulation and neural activity in urinary bladder based on Fourier analysis of its impedance variations was tested in control anesthetized rats and in experimental rats with partial 1-month infravesical obstruction. Pdet was registered by TA-2 (Biola) electromanometer. Bladder impedance was registered by silverchloride electrodes. The rhythmic variations of the bladder impedance were automatically revealed with fast Fourier transform and presented as the dependence of the amplitude of variable component of bioimpedance on frequency. Results. The informative value of the spectrum peak of the bladder impedance at the heart rate frequency as an index of bladder circulation is demonstrated. The individual reactions of normal and obstructive bladders in response to infusion cystometry were recorded. The potency of novel method to assess sympathetic and parasympathetic neural control of the urinary bladder based on the measurements of bioimpedance spectrum peak amplitudes at the very low (0.1 Hz) and respiration (about 1 Hz) frequencies is discussed. Detrusor hypertension was considered as important reason of circulation decrease. While Pdet was increased in 6.1 - 6.5-fold, registered circulation decrease was 26% and 57% in control and tested groups respectively. Conclusion. Research showed potential of a new method of bladder functional assessment. The impedance analyzer created during this work allows simultaneously register Pdet and circulating changes in dynamic. Data shows the difference in circulation and neural activity between normal and hypertrophied bladder. 21 Э к с п е р и м е н Т А Л Ь Н А Я И К Л ИНИ Ч ЕСК А Я У Р О Л О Г И Я № 3 2 0 1 0 w w w. e c u r o. r u э к с п е р и м е н т а л ь н а я у р о л о г и я области тела пузыря и ближе к его шейке. Одновременная регистра- ция показателей давления, базово- го (полного) импеданса и его пере- менной составляющей осуществля- лась оригинальным программно- аппаратным комплексом (Биола), включающим высокочувствитель- ный и малошумящий импеданс- метр с разрешением 250 микро- ом, 4-канальный преобразователь ППШ-04 и ЭВМ. Ритмические вариации импеданса мочевого пу- зыря автоматически выявляли с помощью Фурье-преобразования и представляли как зависимость амплитуды периодической состав- ляющей биоимпеданса от частоты этой составляющей. Измерения производили в раз- ные периоды