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Calcium/calmodulin protein kinase (CaMK)-dependent nitric oxide (NO) and the downstream intracellular messenger cGMP, which is activated by soluble guanylate cyclase (sGC), are believed to induce long-term changes in efficacy of synapses through the activation of protein kinase G (PKG). The aim of this study was to examine the involvement of the CaMKII-dependent NO/sGC/PKG pathway in a novel form of repetitive stimulation-induced spinal reflex potentiation (SRP). A single-pulse test stimulation (TS; 1/30 Hz) on the afferent nerve evoked a single action potential, while repetitive stimulation (RS; 1 Hz) induced a long-lasting SRP that was abolished by a selective Ca2+/CaMKII inhibitor, autocamtide 2-related inhibitory peptide (AIP). Such an inhibitory effect was reversed by a relative excess of nitric oxide synthase (NOS) substrate, l-arginine. In addition, the RS-induced SRP was abolished by pretreatment with the NOS inhibitor, NG-nitro-l-arginine-methyl ester (l-NAME). The sGC activator, protoporphyrin IX (PPIX), reversed the blocking effect caused by l-NAME. On the other hand, a sGC blocker, 1H-[1, 2, 4]oxadiazolo[4, 3-α]quinoxalin-1-one (ODQ), abolished the RS-induced SRP. Intrathecal applications of the membrane-permeable cGMP analog, 8-bromoguanosine 3′,5′-cyclic monophosphate sodium salt monohydrate (8-Br-cGMP), reversed the blocking effect on the RS-induced SRP elicited by the ODQ. Our findings suggest that a CaMKII-dependent NO/sGC/PKG pathway is involved in the RS-induced SRP, which has pathological relevance to hyperalgesia and allodynia.

This study was conducted to investigate whether dorsolateral pontine tegmentum stimulation modulates spinal reflex potentiation (SRP) and whether serotonergic neurotransmission is involved in such a modulation. Reflex activities of the external urethra sphincter (EUS) electromyogram in response to a test stimulation (TS; 1/30 Hz) or repetitive stimulation (RS; 1 Hz) on the pelvic afferent nerve in 35 anesthetized rats were recorded with/without synchronized train pontine stimulation (PS; 300 Hz, 30 ms) and/or intrathecal administrations of 10 microl of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline (NBQX; 100 microM), d-2-amino-5-phosphonovalerate (APV; 100 microM), N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY 100635; 100 microM), and 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT; 100 microM). The TS evoked a single action potential (1.00 +/- 0.00 spikes/stimulation), while the RS produced a long-lasting SRP (16.12 +/- 1.59 spikes/stimulation) that was abolished by APV (1.57 +/- 0.29 spikes/stimulation) and was attenuated by NBQX (7.42 +/- 0.57 spikes/stimulation). Synchronized train PS with RS (PS+RS) produced facilitation in RS-induced SRP (25.17 +/- 2.21 spikes/stimulation). Intrathecal WAY 100635 abolished the facilitation in SRP as a result of the synchronized PS (14.66 +/- 1.58 spikes/stimulation). On the other hand, intrathecal 8-OH-DPAT elicited facilitation in the RS-induced SRP (25.16 +/- 1.05 spikes/stimulation) without synchronized PS. Our findings suggest that dorsolateral pontine tegmentum may modulate N-methyl-d-aspartic acid-dependent SRP via descending serotonergic neurotransmission. This descending modulation may have physiological/pharmacological relevance in the neural controls of urethral closure.

The purposes of this study were to investigate whether the pelvic nerve-to-external urethra sphincter (EUS) reflex potentiation can be induced under physiological conditions and to determine whether glutamatergic neurotransmission is involved in the reflex potentiation. Stimulation-evoked reflex activities, during rhythmic bladder contractions caused by a continuous saline infusion, in 21 anesthetized rats were recorded with/without the intrathecal administration of 10 microl of CNQX (a glutamatergic AMPA receptor antagonist; 100 microM) and APV( a glutamatergic NMDA receptor antagonist; 100 microM). Reflex activities became potentiated following the increment of intravesical pressure (IVP) during the storage phase (2.39 +/- 0.28 spikes/mmHg, n = 21) and the ascending period of the voiding phase (1.46 +/- 0.35 spikes/mmHg, n = 21) and decreased following the decrement of IVP during the descending period of the voiding phase (1.50 +/- 0.33 spikes/mmHg, n = 21). Although it is characterized by a low IVP, a postvoiding reflex potentiation in stimulation-evoked activities was elicited at the critical period after a voiding contraction had just finished (23.95 +/- 8.96 spikes/mmHg, n = 21). The slope of the regression line of evoked activities vs. the IVP during the storage phase was significantly (P0.01) higher than that of the ascending and descending periods of the voiding phase, but there was no statistical difference between the ascending and the descending periods (P0.05). In addition, the slope of the regression line of posttetanic reflex potentiation was significantly higher than that of the storage phase (P0.01). All the slopes of the regression lines decreased after intrathecal CNQX administration (from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.83 +/- 0.31, 0.74 +/- 0.12, 0.76 +/- 0.12, and 4.31 +/- 3.71 spikes/mmHg in storage, ascending and descending period of the voiding phase, and postvoiding potentiation, respectively; all P0.01, n = 10). The slopes of the regression lines became almost horizontal after intrathecal APV administration (from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.16 +/- 0.12, 0.21 +/- 0.07, 0.18 +/- 0.05, and 0.23 +/- 0.76 spikes/mmHg in storage, ascending and descending period of voiding phase, and postvoiding potentiation, respectively; all P0.01, n = 10). Our results suggest that a potentiation in the pelvic nerve-to-EUS reflex can be induced under physiological conditions and the glutamatergic mechanism appears to be involved in this reflex potentiation.

We showed previously that lipopolysaccharide (LPS) induces noncholinergic airway hyperreactivity to capsaicin via an upregulation of tachykinin synthesis. This study was designed to test whether double-stranded preprotachykinin (ds PPT) RNA, RNA interference (RNAi), prevents the LPS-induced alterations. First, cultured primary nodose ganglial cells of newborn Brown-Norway rats were divided into four groups: control; LPS; LPS+RNAi; and LPS+RNAi+liposome. Second, young Brown-Norway rats for the in vivo study were divided into three groups (control; LPS; and LPS+RNAi), and ds PPT RNA was microinjected bilaterally into the nodose ganglia in the LPS+RNAi group. Then, ganglial cells were collected from the culture whereas the nodose ganglia and lungs were sampled from the animals, and PPT mRNA and substance P (SP) levels were analyzed. Also, airway reactivity to capsaicin was performed in vivo. LPS induced significant increases in PPT mRNA and SP levels in vitro and in vivo and an increase in airway reactivity to capsaicin in vivo. However, ds PPT RNA, but not scrambled RNA, prevented all LPS-induced alterations. The effect of ds PPT RNA was not enhanced by liposome in vitro. Therefore, we demonstrated that the local application of RNAi prevents effectively the activation of the noncholinergic system modulating the lungs/airways.

We explored the dysfunction of tachykinins on monocrotaline (MCT)-induced pulmonary hypertension by using double-stranded preprotachykinin (ds PPT) RNA and neurokinin receptor (NK) antagonists. Here, we showed the possibility to attenuate the PPT gene expression by ds RNA, RNA interference (RNAi), in fully developed tissue of rats. We designed four groups (control, MCT, RNAi + MCT, and solvent + MCT) of experiments in series 1 and seven groups (control, MCT, MCT + CP-96345-3.4, MCT + CP-96345-10, MCT + CP-96344-10, MCT + SR-48968, and MCT + SR-48965) of experiments in series 2. Rats in the control groups received saline injection. MCT-treated rats received a single MCT injection (60 mg/kg sc). One day prior to MCT, bilateral nodose ganglia were microinjected with ds PPT RNA in rats of the RNAi + MCT group or with solvent in the solvent + MCT group. Beginning from 1 day post-MCT, MCT-treated rats received a daily injection of the NK1 receptor antagonist, CP-96345 (3.4 or 10 mg/kg ip) or its inactive enantiomer CP-96344 (10 mg/kg ip). The NK2 receptor antagonist SR-48968 (3 mg/kg ip) or its inactive enantiomer SR-48965 (3 mg/kg ip) was injected to MCT-treated rats every other day starting 1 day post-MCT. Functional study was carried out 2 weeks (series 1) or 3 weeks (series 2) after MCT. MCT induced right ventricular hypertrophy, as well as increases in pulmonary arterial pressure, PPT mRNA (nodose ganglia and lung tissue), and lung tissue substance P level. All of the above MCT-induced alterations were attenuated by either RNAi or NK receptor antagonists. We conclude that tachykinins play an important role in MCT-induced pulmonary hypertension.

We attempted to evaluate whether the antioxidants 1,3-dimethyl-2-thiourea (DMTU) and hexa(sulfobutyl)fullerenes (FC 4 S) attenuate monocrotaline (MCT)-induced pulmonary hypertension (PH) by lowering lung substance P (SP) in Wistar rats. Sixty-three rats weighing 297 ± 8 g were divided into six groups: control; MCT; capsaicin + MCT; MCT + DMTU-1; MCT + DMTU-2; and MCT + FC 4 S. Three weeks before the functional study, saline was injected into each control rat, whereas each MCT rat received 60 mg/kg sc MCT. Rats in the third group received capsaicin pretreatment followed by MCT. A 3-day injection of DMTU was performed during the early (DMTU-1) or the late (DMTU-2) post-MCT period. For the last group, each MCT-treated rat received a daily FC 4 S injection until the commencement of the functional study. Compared to the control group, MCT caused significant increases in pulmonary arterial pressure (Ppa), right ventricular hypertropy, pulmonary arterial medial thickness, lung SP level, and luminol-enhanced chemiluminescence counts in bronchoalveolar lavage. Both capsaicin and antioxidants significantly attenuated the above MCT-induced alterations. SP-induced acute increase in Ppa was exaggerated in MCT-treated rats. These results suggest that oxygen radicals play an important role in MCT-induced PH via elevating lung SP level.

Acute bacterial meningitis (ABM) is a serious disease with severe neurological sequelae. The intense calcium-mediated microglial activation and subsequently pro-inflammatory cytokine release plays an important role in eliciting ABM-related oxidative damage. Considering resveratrol possesses significant anti-inflammatory and anti-oxidative properties, the present study aims to determine whether resveratrol would exert beneficial effects on hippocampal neurons following ABM. ABM was induced by inoculating Klebsiella pneumoniae into adult rats intraventricularly. The time-of-flight secondary ion mass spectrometry (TOF-SIMS), Griffonia simplicifolia isolectin-B4 (GSA-IB4) and ionized calcium binding adaptor molecule 1 (Iba1) immunohistochemistry, enzyme-linked immunosorbent assay as well as malondialdehyde (MDA) measurement were used to examine the calcium expression, microglial activation, pro-inflammatory cytokine level, and extent of oxidative stress, respectively. In ABM rats, strong calcium signaling associated with enhanced microglial activation was observed in hippocampus. Increased microglial expression was coincided with intense production of pro-inflammatory cytokines and oxidative damage. However, in rats receiving resveratrol after ABM, the calcium intensity, microglial activation, pro-inflammatory cytokine and MDA levels were all significantly decreased. Quantitative data showed that much more hippocampal neurons were survived in resveratrol-treated rats following ABM. As resveratrol successfully rescues hippocampal neurons from ABM by suppressing the calcium-mediated microglial activation, therapeutic use of resveratrol may act as a promising strategy to counteract the ABM-induced neurological damage.

The purpose of this study was to determine the effects of an extract from Moringa oleifera (MO) on the development of monocrotaline (MCT)-induced pulmonary hypertension (PH) in Wistar rats. An ethanol extraction was performed on dried MO leaves, and HPLC analysis identified niaziridin and niazirin in the extract. PH was induced with a single subcutaneous injection of MCT (60 mg/kg) which resulted in increases in pulmonary arterial blood pressure (Ppa) and in thickening of the pulmonary arterial medial layer in the rats. Three weeks after induction, acute administration of the MO extract to the rats decreased Ppa in a dose-dependent manner that reached statistical significance at a dose of 4.5 mg of freeze-dried extract per kg body weight. The reduction in Ppa suggested that the extract directly relaxed the pulmonary arteries. To assay the effects of chronic administration of the MO extract on PH, control, MCT and MCT+MO groups were designated. Rats in the control group received a saline injection; the MCT and MCT+MO groups received MCT to induce PH. During the third week after MCT treatment, the MCT+MO group received daily i.p. injections of the MO extract (4.5 mg of freeze-dried extract/kg of body weight). Compared to the control group, the MCT group had higher Ppa and thicker medial layers in the pulmonary arteries. Chronic treatments with the MO extract reversed the MCT-induced changes. Additionally, the MCT group had a significant elevation in superoxide dismutase activity when normalized by the MO extract treatments. In conclusion, the MO extract successfully attenuated the development of PH via direct vasodilatation and a potential increase in antioxidant activity.

Perinatal hypoxia has been observed to cause more aggressive pulmonary hypertension in human. Several mediators such as reactive oxygen species (ROS) and substance P are believed to be crucial in the mechanism of inducing pulmonary hypertension. This study was designed to test whether substance P and ROS play a role in perinatal hypoxia-exaggerated, monocrotaline (MCT)-induced pulmonary hypertension. Normoxic Wistar rats (weighing 258 ±9 g, n = 31) were divided into two groups: control (n = 16) and MCT (n = 15). Perinatal hypoxia Wistar rats (weighing 260 ±19 g, n = 49) were divided into six groups: Hypoxia (n = 8), Hypoxia+MCT (n = 8), Hypoxia+capsaicin (CP)+MCT (n = 7), Hypoxia+MCT+1,3-dimethyl-2- thiourea (DMTU)E (n = 10), Hypoxia+MCT+DMTU(subscript L) (n = 9), and Hypoxia+MCT+ hexa(sulfobutyl) fullerenes (HSF) (n = 7). Rats in the control group received saline injections. MCT (60 mg/kg, s.c.) was given three weeks prior to the functional examination. Chronic capsaicin pretreatment was performed to deplete substance P. Hydroxyl radical scavenger DMTU (500 mg/kg) was intraperitoneally (i.p.) injected early (DMTU(subscript E)) or late (DMTU(subscript L)) after MCT. Antioxidant HSF (10 mg/kg, i.p.) was given once daily for three weeks following MCT. MCT treatment caused significant increases in pulmonary arterial pressure (Ppa) and substance P level in lung tissue in normoxic rats. The MCT-induced increase in pulmonary arterial blood pressure was exaggerated by perinatal hypoxia, but this exaggeration was attenuated by either capsaicin pretreatment or antioxidant administrations. These results suggest that both ROS and substance P are involved in perinatal hypoxia-augmented, MCT-induced pulmonary hypertension.

Recently, we demonstrated a chronic neurosteroid-dependent inhibition of activity-dependent spinal reflex potentiation (SRP), but it remains unclear whether neurosteroids acutely modulate SRP induction. This study shows progesterone as well as two of its 3α,5α-derivatives, allopregnalonone and 3α,5α-tetrahydrodeoxycorticosterone (THDOC), to be capable of producing acute GABAA receptor (GABAAR)-dependent inhibition of SRP. When compared with test simulation (1 stimulation/30 s) of pelvic afferent nerves that evoked a baseline reflex activity in an external urethra sphincter electromyogram, repetitive stimulation (RS; 1 stimulation/1 s) induced SRP characterized by an increase in the evoked activity. Intrathecal progesterone (3–30 μM, 10 μl) at 10 min before stimulation onset dose dependently prevented RS induction. Intrathecal allopregnalonone (10 μM, 10 μl it) and THDOC (10 μM, 10 μl it) also prevented the SRP caused by RS. Pretreatment with the GABAAR antagonist bicuculline (10 μM, 10 μl it) at 1 min before progesterone/neurosteroid injection attenuated the inhibition of SRP caused by progesterone, allopregnanolone, and THDOC. Results suggest that progesterone and its neurosteroid metabolites may be crucial to the development of pelvic visceral neuropathic/postinflammatory pain and imply clinical use of neurosteroids, such as allopregnanolone and THDOC, for visceral pain treatment.

The pressor effects on blood pressure (BP) elicited by electro-acupuncture (Ea) stimulations and vesico-vascular reflex (VVR) were investigated in anesthetized rats. Twenty adult female Sprague-Dawley rats were used throughout this study. Two acupoints, the Hoku (Li-4) and the Tsusanli (St-36), were tested by a low frequency Ea (LFEa, 2 Hz) and a high frequency Ea (HFEa, 20 Hz) with intensities 20 times that of the motor threshold. Ea at Tsusanli elicited no pressor effects (98.15 +/- 4.10% and 101.43 +/- 3.96% of pre-stimulation control in LFEa and HFEa, respectively) whereas pressor effects could be induced by Ea stimulations at Hoku (126.3 +/- 3.3% and 136.3 +/- 3.8% of pre-stimulation control in LFEa and HFEa, respectively, P < 0.01, n=10). In addition, the patterns of pressor effects elicited by LFEa and HFEa at Hoku were different, i.e., LFEa at Hoku elicited a tonic pressor effect, while HFEa elicited a phasic one. The VVR induced by bladder isovolumic saline distension also elicited a pressor effect on BP (119.2 +/- 2.2%, P < 0.01, n=10) in the same preparations during bladder contractions. The VVR did not modify the Ea-induced pressor responses, and vice versa, when both of them were superimposed. All the results suggested that the pressor effects elicited by the VVR and the Ea stimulation were additive responses. In addition, for future clinical application, our findings may imply that patients should be carefully monitored for signs and symptoms of autonomic dysfunction during clinical acupuncture treatments.

This study was conducted to investigate the possible neurotransmitter that activates the descending pathways coming from the dorsolateral pontine tegmentum (DPT) to modulate spinal pelvic-urethra reflex potentiation. External urethra sphincter electromyogram (EUSE) activity in response to test stimulation (TS, 1/30 Hz) and repetitive stimulation (RS, 1 Hz) on the pelvic afferent nerve of 63 anesthetized rats were recorded with or without microinjection of nicotinic cholinergic receptor (nAChR) agonists, ACh and nicotine, to the DPT. TS evoked a baseline reflex activity with a single action potential (1.00 ± 0.00 spikes/stimulation, n = 40), whereas RS produced a long-lasting reflex potentiation (16.14 ± 0.96 spikes/stimulation, n = 40) that was abolished by d-2-amino-5-phosphonovaleric acid (1.60 ± 0.89 spikes/stimulation, n = 40) and was attenuated by 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline (7.10 ± 0.84 spikes/stimulation, n = 40). ACh and nicotine microinjections to DPT both produced facilitation on the RS-induced reflex potentiation (23.57 ± 2.23 and 28.29 ± 2.36 spikes/stimulation, P < 0.01, n = 10 and 20, respectively). Pretreatment of selective nicotinic receptor antagonist, chlorisondamine, reversed the facilitation on RS-induced reflex potentiation caused by nicotine (19.41 ± 1.21 spikes/stimulation, P < 0.01, n = 10) Intrathecal WAY-100635 and spinal transection at the T1level both abolished the facilitation on reflex potentiation resulting from the DPT nicotine injection (12.86 ± 3.13 and 15.57 ± 1.72 spikes/stimulation, P < 0.01, n = 10 each). Our findings suggest that activation of nAChR at DPT may modulate N-methyl-d-aspartic acid-dependent reflex potentiation via descending serotonergic neurotransmission. This descending modulation may have physiological/pathological relevance in the neural controls of urethral closure.

The current study investigates whether the spinal pelvic nerve-to-external urethra sphincter (EUS) reflex potentiation can be induced by a mechanical stimulation and whether the glutamatergic mechanism is involved in yielding such a reflex potentiation. The external urethra sphincter electromyogram (EUSE) activity, evoked by a single or by repetitive pelvic nerve stimulation, in 30 anesthetized rats was recorded with/without bladder saline distension. Without saline distension (0 cmH(2)O), a single pulse nerve stimulation evoked a single action potential in the reflex activity, whereas repetitive pelvic stimulation and saline distension (6 approximately 20 cmH(2)O) both elicited a long-lasting reflex potentiation (20.05 +/- 3.21 and 75.01 +/- 9.87 spikes/stimulation, respectively). The saline distension-induced pelvic nerve-to-EUS reflex potentiation was abolished by D-2-amino-5-phosphonovalerate [APV; a glutamatergic N -methyl-D-aspartic acid (NMDA) receptor antagonist; 100 microM, 10 microl, 1.72 +/- 0.31 spikes/stimulation] and attenuated by 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline [NBQX; a glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate (AMPA) receptor antagonist; 100 microM, 10 microl, 26.16 +/- 7.27 spikes/stimulation], but was not affected by bicuculline (a GABAergic antagonist; 100 microM, 10 microl, 53.62 +/- 15.54 spikes/stimulation). Intrathecal administration of glutamate (31.12 +/- 8.25 spikes/stimulation, 100 microM, 10 microl) and NMDA (26.25 +/- 4.12 spikes/stimulation, 100 microM, 10 microl) both induced a long-lasting pelvic nerve-to-EUS reflex potentiation without saline distension, which was similar to the findings observed from saline distension only. The duration of the contraction wave of the urethra was elongated by the saline distension-induced pelvic nerve-to-EUS reflex potentiation, whereas the peak pressure of the contraction wave was not affected. Our findings suggest that saline distension in the bladder elicits a pelvic nerve-to-EUS reflex potentiation and the glutamatergic mechanism contributes to the presence of such a reflex potentiation.

To clarify the contributions of sensory inputs and glutamate transmissions to the spinal micturition reflex.Cystometrogram and external urethral sphincter electromyogram activities evaluated the L6 and/or S1 levels.Changes in intravesicular pressure (IVP) in response to saline infusion (0.1 ml/min) were found after unilateral dorsal root rhizotomy at the L6 level, which showed significant increases in threshold pressure (rhizotomized vs. control: 14.25 +/- 0.82 vs. 8.40 +/- 0.69 cmH(2)O, P0.01, n = 28), post-voiding pressure (7.66 +/- 0.56 vs. 5.42 +/- 0.52 cmH(2)O, P0.01, n = 28), holding duration (135.06 +/- 23.6 vs. 77.73 +/- 13.56 sec, P0.05, n = 28), and inter-contraction interval (140.62 +/- 23.29 vs. 82.40 +/- 13.57 sec, P0.05, n = 28). Several (mean = 2.32 +/- 1.31 vs. 0.12 +/- 0.21, P0.01, n = 28, P0.01, n = 28) non-voiding contractions with gradual increase in IVP were found ahead of voiding contraction after rhizotomy. An additional dorsal root rhizotomy at the ipsilateral S1 level caused further increases in urodynamic parameters (threshold pressure, 18.18 +/- 1.67 cmH(2)O, P0.01; post-voiding pressure 8.07 +/- 0.96 cmH(2)O, P0.01; holding duration, 211.44 +/- 42.54 sec, P0.01; inter-contraction interval, 264.2 +/- 59.99 sec, P0.05; non-voiding contractions, 4.41 +/- 2.12, P0.01, n = 7). Intrathecal glutamate (100 microM, 10 microl) ameliorated all the pathological conditions induced by unilateral dorsal root rhizotomy at the L6 level in a dose dependent manner (ED(50) = 1.25 +/- 10(-5)). Intrathecal CNQX (6-cyano-7-nitroquinoxaline-2,3-dione; 100 microM, 10 microl) and APV (D-2-amino-5-phosphonovaleric acid; 100 microM, 10 microl) injections after rhizotomy at the L6 level induced disturbances similar to that caused by an additional rhizotomy at ipsilateral S1 level. Wherease, glutamate (100 microM, 10 microl) reversed the disturbances caused by CNQX but showed no effect on that by APV.Acute partial sensory deprivation caused acute impaired micturition reflex in rat models. In addition, glutamatergic NMDA and AMPA receptors are important for mediating these impairments in micturition reflex.

The effects of gonadal steroids on glutamate-mediated pelvic nerve-to-urethra reflex (PUR) plasticity were investigated in rats, which received a sham operation (Sham), ovariectomy (OVX), or ovariectomy with daily supplemental estrogen (50 microg/kg, OVX + E2). The magnitude of the repetitive stimulation (RS, 1 Hz)-induced potentiation in PUR activity decreased significantly in the OVX group when compared with the Sham groups (18.09 +/- 3.91 and 7.40 +/- 1.03 spikes/stimulation in Sham and OVX group; respectively, P < 0.01, n = 21). Supplemental estrogen (OVX + E2, 12.60 +/- 1.49 spikes/stimulation) significantly reversed the decrease in RS-induced PUR potentiation caused by OVX (P < 0.01, n = 21). The magnitude of the RS-induced potentiation in PUR activity decreased significantly after intrathecal 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline [(20 microm, 10 microl), from 18.09 +/- 3.91 to 10.40 +/- 0.81, from 7.40 +/- 1.03 to 3.20 +/- 0.94, and from 12.60 +/- 1.49 to 8.06 +/- 0.32 spikes/stimulation in Sham, OVX, and OVX + E2, respectively, P < 0.01, n = 18] and D-2-amino-5-phosphonoraleric acid [(100 microm, 10 microl), from 18.09 +/- 3.91 to 1.04 +/- 0.12, from 7.40 +/- 1.03 to 1.06 +/- 0.22, and from 12.60 +/- 1.49 to 0.98 +/- 0.25 spikes/stimulation in Sham, OVX, and OVX + E2, respectively, P < 0.01, n = 18]. In addition, potentiation in PUR activities was induced by intrathecal l-glutamate (0.1 mm, 10 microl, from 1.04 +/- 0.02 to 21.60 +/- 0.93, from 1.10 +/- 0.06 to 8.40 +/- 1.50, and from 1.03 +/- 0.03 to 18.04 +/- 0.84 spikes/stimulation in Sham, OVX, and OVX + E2, respectively, P < 0.01, n = 18) and N-methyl-D-aspartic acid (0.1 mm, 10 microl, from 1.04 +/- 0.02 to 14.80 +/- 0.97, from 1.10 +/- 0.06 to 4.60 +/- 0.48, and from 1.03 +/- 0.03 to 9.09 +/- 0.63 spikes/stimulation in Sham, OVX, and OVX + E2); N-methyl-D-aspartic acid-mediated PUR plasticity in female rats and may contribute to alterations in urinary dysfunction after menopause.

To clarify the contributions of parasympathetic inputs and outputs to the micturition reflex.Intra-vesical pressure (IVP), external urethral sphincter electromyogram (EMG), pelvic afferent nerve activities (PANA), and pelvic efferent nerve activities (PENA) as well as the time-derived IVP (dIVP, an index of bladder contractility) were evaluated in intact and acute dorsal or ventral root(s) rhizotomized (DRX and VRX, respectively) rats.In DRX rats, when compared with that in intact stage, the voiding frequency was decreased (75 +/- 15% of intact, P0.05, n = 8), while the threshold pressure to trigger voiding contractions was significantly increased (187 +/- 75% of intact, P0.05, n = 8). In addition, several insufficient contractions (5.3 +/- 3.5 contractions/voiding, P0.05, n = 8) occurred in ahead of each voiding contraction. On the other hand, in VRX rats, the peak and rebound IVP were significantly decreased (90 +/- 3.5% and 75 +/- 11.3% of intact, P0.01, n = 8), while the threshold pressure was not affected (102 +/- 11% of intact, P = NS, n = 8). The time-derived parameters were significantly decreased in VRX (peak dIVP, 78 +/- 10.2%, rebound dIVP, 75 +/- 15.6%, minimal dIVP, 68 +/- 14% of intact, P0.01, n = 8) but only peak dIVP was decreased (85 +/- 11% of intact, P0.01, n = 8) in DRX rats.Acute selective DRX and VRX rat can be an animal model to investigate peripheral neural control in micturition functions.

The pharmacological activity of CL-065 (trans-3-acetamido-2, 2-dimethyl-4-hydroxy-3, 4-dihydro-2H-1-benzopyran-6-carbonitrite) was investigated in anaesthetized spontaneously hypertensive rats (SHR) and isolated thoracic aorta of Sprague-Dawley rats. The intravenous administration of CL-065 (0.1–2.0 mg kg−1) to anaesthetized SHR induced a dose-dependent reduction of mean arterial pressure (MAP) with maximum effect approximately 5 min after injection and which persisted for over 3 h. CL-065 also induced a reflex tachycardia which seemed to parallel the time course of the hypotensive effect. The hypotensive effect of CL-065 was blocked by pretreatment with glibenclamide (5 mg kg−1, i.v.), a specific ATP-sensitive potassium (KATP) channel blocker. Moreover, CL-065 (0.01–10 μM) resulted in dose-dependent vasodilatory effects on phenylephrine (0.3 μM)-induced vasoconstriction in isolated thoracic aorta. The vasorelaxation elicited by CL-065 was antagonized competitively by pretreatment with glibenclamide (0.1–1.0 μM; pA2 = 6.90 ± 0.09; slope = 1.03 ± 0.18). Similarly, the other two KATP-channel openers cromakalim (1.0 nM–1.0 μM) and nicorandil (0.1–30 μM) also induced vasorelaxation in thoracic aorta. The EC50 of cromakalim, CL-065 and nicorandil (i.e. the doses having half the maximum effect) were approximately 0.083, 0.17, and 4.5 μM, respectively, for phenylephrine (0.3 μM)-induced vasoconstriction in isolated thoracic aorta. Moreover, increased extracellular potassium levels (20–60 mM) resulted in concentration-dependent attenuation of the vasodilator effect of CL-065. In conclusion, CL-065 induces a depressor effect via activation of KATP channels.