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- Daiuto, Sergio A., et al.
(författare)
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Angiotensinergic and GABAergic transmission in the medial preoptic area: role in urinary bladder and cardiovascular control in female rats
- 2023
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Ingår i: Frontiers in Physiology. - 1664-042X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The medial preoptic area (mPOA) participates in thermoregulatory control and blood pressure modulation as shown by studies with electrical stimulation of this area or cobalt chloride injection, a non-selective synapse inhibitor. This study aimed to investigate whether angiotensin II (Ang II) and GABA could act or not in the mPOA to mediate the cardiovascular and micturition control pathways. Methods: Female Wistar rats were submitted to stereotaxic surgery for implantation of a guide cannula into the mPOA 7days prior to the experiments. Afterwards, the animals were isoflurane- anesthetized and submitted to the catheterization of the femoral artery and vein and urinary bladder cannulation for mean arterial pressure (MAP), heart rate (HR), and intravesical pressure (IP) recordings, respectively. After the baseline MAP, HR, and IP recordings for 15min, Ang II (0.1nM, 1μL), losartan (AT-1 receptor antagonist, 100nM, 1μL), GABA (50mM, 1μL) or saline (1μL) were injected into the mPOA, and the variables were measured for additional 30min. In a different group of rats, the AT-1 receptor, angiotensin II converting enzyme (ACE), and GABAa receptor gene expression was evaluated in mPOA samples by qPCR. The data are as mean ± SEM and submitted to One-way ANOVA (Tukey posttest) or paired Student t-test (P <0.05). Results: The injection of Ang II into the mPOA evoked a significant hypotension (−37±10mmHg, n = 6, p = 0.024) and bradycardia (−47 ± 20bpm, p = 0.030) compared to saline (+1 ± 1mmHg and +6 ± 2bpm, n = 6). A significant increase in IP was observed after Ang II injection into the mPOA (+72.25 ± 17.91%, p = 0.015 vs. −1.80 ± 2.98%, n = 6, saline). No significant changes were observed in MAP, HR and IP after the losartan injection in the mPOA compared to saline injection. Injection of GABA into the mPOA evoked a significant fall in MAP and HR (−68 ± 2mmHg, n = 6, p < 0.0001 and −115 ± 14bpm, n = 6, p = 0.0002 vs. −1 ± 1mmHg and +4 ± 2bpm, n = 6, saline), but no significant changes were observed in IP. The AT-1 receptor, ACE and GABAa receptor mRNA expression was observed in all mPOA samples. Discussion: Therefore, in female rats, Ang II mediated transmission in the mPOA is involved in the cardiovascular regulation and in the control of central micturition pathways. A phasic control dependent on AT-1 receptors in the mPOA seems to be involved in the regulation of those cardiovascular and intravesical 3 parameters. In contrast, GABAergic transmission in the mPOA participates in the pathways of cardiovascular control in anesthetized female rats, nevertheless, this neurotransmission is not involved in the micturition control.
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| 2. |
- de Carvalho, Rodrigo P, et al.
(författare)
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GABAergic and glutamatergic transmission reveals novel cardiovascular and urinary bladder control features in the shell nucleus accumbens.
- 2023
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Ingår i: Brain research. - 1872-6240. ; 1818
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Tidskriftsartikel (refereegranskat)abstract
- The shell Nucleus Accumbens (NAcc) projects to the lateral preoptic area, which is involved in the central micturition control and receives inputs from medullary areas involved in cardiovascular control. We investigated the role of GABAergic and glutamatergic transmission in the shell NAcc on intravesical pressure (IP) and cardiovascular control. Male Wistar rats with guide cannulas implanted bilaterally in the shell NAcc 7days prior to the experiments were anesthetized with 2% isoflurane in 100% O2 and subjected to cannulation of the femoral artery and vein for mean arterial pressure (MAP) and heart rate recordings (HR) and infusion of drugs, respectively. The urinary bladder (UB) was cannulated for IP measurement. A Doppler flow probe was placed around the renal arterial for renal blood flow (RBF) measurement. After the baseline MAP, HR, IP and RBF recordings for 15min, GABA or bicuculline methiodate (BMI) or L-glutamate or kynurenic acid (KYN) or saline (vehicle) were bilaterally injected into the shell NAcc and the variables were measured for 30min. Data are as mean±SEM and submitted to Student́s t test. GABA injections into the shell NAcc evoked a significant fall in MAP and HR and increased IP and RC compared to saline. L-glutamate in the shell NAcc increased MAP, HR and IP and reduced RC. Injections of BMI and KYN elicited no changes in the variables recorded. Therefore, the GABAergic and glutamatergic transmissions in neurons in the shell NAcc are involved in the neural pathways responsible for the central cardiovascular control and UB regulation.
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| 3. |
- Lopes, Fábio I, et al.
(författare)
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Activation of 5-HT3 receptors in the medulla oblongata is involved in the phasic control of urinary bladder.
- 2022
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Ingår i: Neuroscience letters. - : Elsevier BV. - 1872-7972 .- 0304-3940. ; 790
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Tidskriftsartikel (refereegranskat)abstract
- 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 5days 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±6mmHg) compared to saline (0.34±0.64% and -2±2mmHg), 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±4mmHg) and heart rate (36±9bpm) 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.
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