Dept. Morphology and Physiology, Faculdade de Medicina do ABC, Centro Universitario FMABC, Santo Andre, SP, Brazil.
Dept. Morphology and Physiology, Faculdade de Medicina do ABC, Centro Universitario FMABC, Santo Andre, SP, Brazil.
Neurosci Lett. 2022 Nov 1;790:136886. doi: 10.1016/j.neulet.2022.136886. Epub 2022 Sep 28.
The control of micturition depends on reflex mechanisms, however, it undergoes modulation from cortex, pons and medullary areas. This study investigated if the activation of 5-HT3 receptors in the medulla influences the urinary bladder (UB) regulation in rats. Isoflurane female Wistar rats were submitted to catheterization of the femoral artery and vein for mean arterial pressure (MAP) and heart rate (HR) recordings and injection of drugs, respectively. The UB was cannulated for intravesical pressure (IP) measurement. The Doppler flow probe was placed around the left renal artery for renal conductance (RC) recordings. Phenylbiguanide (PB) and granisetron (GN) were injected into the 4th brain ventricle in rats with guide cannulas implanted 5 days prior to the experiments; or PB and GN were randomly injected intravenously or applied topically (in situ) on the UB. PB injection into 4th V significantly increased IP (68.67 ± 11.70%) and decreased MAP (-29 ± 6 mmHg) compared to saline (0.34 ± 0.64% and -2 ± 2 mmHg), with no changes in the HR and RC. GN injection into the 4th V did not significantly change the IP and RC compared to saline, nevertheless, significantly increased MAP (25 ± 4 mmHg) and heart rate (36 ± 9 bpm) compared to saline. Intravenous PB and GN only produced cardiovascular effects, whilst PB but not GN in situ on the UB evoked increase in IP (111.60 ± 30.36%). Therefore, the activation of 5HT-3 receptors in medullary areas increases the intravesical pressure and these receptors are involved in the phasic control of UB. In contrast, 5-HT3 receptors in the medulla oblongata are involved in the pathways of the tonic control of the cardiovascular system. The activation of 5-HT3 receptors in the bladder cause increase in intravesical pressure and this regulation seem to be under phasic control as the blockade of such receptors elicits no changes in baseline intravesical pressure.
排尿控制依赖于反射机制,但它也受到大脑皮层、脑桥和延髓区域的调节。本研究探讨了延髓 5-HT3 受体的激活是否会影响大鼠的膀胱(UB)调节。异氟烷麻醉的雌性 Wistar 大鼠接受股动脉和静脉导管插入术,用于测量平均动脉压(MAP)和心率(HR),并分别进行药物注射。UB 进行了膀胱内压(IP)测量。多普勒血流探头放置在左肾动脉周围,用于记录肾电导(RC)。在实验前 5 天植入引导套管的大鼠中,将苯丁胍(PB)和格拉司琼(GN)注入第四脑室内;或静脉内随机注射 PB 和 GN 或局部(原位)应用于 UB。与生理盐水(0.34±0.64%和-2±2mmHg)相比,第四脑室注射 PB 可显著增加 IP(68.67±11.70%)和降低 MAP(-29±6mmHg),而 HR 和 RC 没有变化。与生理盐水相比,第四脑室注射 GN 对 IP 和 RC 没有显著影响,但显著增加 MAP(25±4mmHg)和心率(36±9bpm)。静脉内注射 PB 和 GN 仅产生心血管作用,而 PB 但不是 GN 原位作用于 UB 可引起 IP 增加(111.60±30.36%)。因此,延髓区 5HT-3 受体的激活增加了膀胱内压,这些受体参与了 UB 的相位控制。相反,延髓中的 5-HT3 受体参与了心血管系统的紧张性控制途径。膀胱中 5-HT3 受体的激活导致膀胱内压增加,这种调节似乎受到相位控制,因为阻断这些受体不会导致基础膀胱内压发生变化。