Serotonin in the rat prefrontal cortex controls the micturition reflex through 5-hydroxytryptamine 2A and 5-hydroxytryptamine 7 receptors.
大鼠前额叶皮质中的 5-羟色胺通过 5-羟色胺 2A 和 5-羟色胺 7 受体控制排尿反射。
- 作者列表："Chiba H","Kitta T","Ohmura Y","Higuchi M","Kon M","Nakamura M","Yoshioka M","Shinohara N
OBJECTIVES:To identify the types of serotonin (5-hydroxytryptamine) receptors of the prefrontal cortex related to the micturition reflex. METHODS:Female Sprague-Dawley rats and a microinjection method were used for this study. Stainless steel guide cannulas were implanted bilaterally into the prefrontal cortex, and a polyethylene catheter was inserted into the bladder. Cystometric parameters (intercontraction interval and maximum voiding pressure) were measured before and after injection of any one of six specific antagonists of 5-hydroxytriptamine receptors (5-hydroxytryptamine 1A, 5-hydroxytryptamine 2A, 5-hydroxytryptamine 2C, 5-hydroxytryptamine 3, 5-hydroxytryptamine 4 and 5-hydroxytryptamine 7) into the prefrontal cortex. The prefrontal cortex was divided into two regions, namely the prelimbic cortex and the infralimbic cortex. The experiments were carried out in conscious and free-moving rats. RESULTS:The intercontraction interval value increased significantly after injection of the 5-hydroxytriptamine 2A receptor antagonist, MDL11939, into the prelimbic cortex of the rat prefrontal cortex (7.68 ± 1.28 vs 9.02 ± 1.41 min, P < 0.05), whereas the intercontraction interval value decreased significantly after injection of the 5-hydroxytriptamine 7 antagonist SB269970 into the prelimbic cortex (9.42 ± 0.39 vs 8.14 ± 0.71 min, P < 0.05). The intercontraction interval was unaffected by injection of either of these two antagonists into the infralimbic cortex. The other four antagonists (5-hydroxytryptamine 1A, 5-hydroxytryptamine 2C, 5-hydroxytryptamine 3 and 5-hydroxytryptamine 4) had no effect on the intercontraction interval after injection into the prelimbic cortex and the infralimbic cortex. The maximum voiding pressure was unaffected by injection of any one of the six 5-hydroxytriptamine antagonists into the prelimbic cortex and infralimbic cortex. CONCLUSIONS:In the rat prefrontal cortex5-hydroxytryptamine 2A receptors excite the micturition reflex, whereas 5-hydroxytryptamine 7 receptors inhibit this reflex.
目的: 确定与排尿反射相关的前额叶皮质 5-羟色胺 (5-羟色胺) 受体的类型。 方法: 采用雌性 Sprague-Dawley 大鼠和微量注射方法进行研究。将不锈钢导向套管双侧植入前额叶皮质，将聚乙烯导管插入膀胱。在注射 6 种 5-羟色胺受体特异性拮抗剂 (5-羟色胺 1A 、 5-羟色胺 2A 、 5-羟色胺 2C 、 5-羟色胺 3 、 5-羟色胺 4 和 5-羟色胺 7) 进入前额叶皮质。前额叶皮层被分为两个区域，即边缘前皮层和边缘下皮层。实验在清醒和自由活动的大鼠中进行。 结果: 大鼠前额叶前皮质注射 5-羟基雷公藤甲素 2A 受体拮抗剂 MDL11939 后，收缩间期值显著增加 (7.68 ± 1.28 vs 9.02 ± 1.41 min, P <0.05)，而在边缘前皮质注射 5-羟基雷公藤胺 7 拮抗剂 SB269970 后，收缩间期值显著降低(9.42 ± 0.39 vs 8.14 ± 0.71 min，P <0.05)。通过将这两种拮抗剂中的任何一种注射到垂体下皮质，收缩间期不受影响。其他 4 种拮抗剂 (5-羟色胺 1A 、 5-羟色胺 2C 、 5-羟色胺 3 和 5-羟色胺 4) 对注射到边缘前皮质和边缘下皮质后的收缩间隔没有影响。最大排尿压力不受 6 种 5-羟基雷公藤胺拮抗剂中任何一种注射到边缘前皮质和边缘下皮质的影响。 结论: 在大鼠前额叶 cortex5-hydroxytryptamine 2A 受体兴奋排尿反射，而 5-羟色胺 7 受体抑制这一反射。
METHODS::In recent years, transcranial electrical stimulation (tES) has been used to improve cognitive and perceptual abilities and to boost learning. In the visual domain, transcranial random noise stimulation (tRNS), a type of tES in which electric current is randomly alternating in between two electrodes at high frequency, has shown potential in inducing long lasting perceptual improvements when coupled with tasks such as contrast detection. However, its cortical mechanisms and online effects have not been fully understood yet, and it is still unclear whether these long-term improvements are due to early-stage perceptual enhancements of contrast sensitivity or later stage mechanisms such as learning consolidation. Here we tested tRNS effects on multiple spatial frequencies and orientation, showing that tRNS enhances detection of a low contrast Gabor, but only for oblique orientation and high spatial frequency (12 cycles per degree of visual angle). No improvement was observed for low contrast and vertical stimuli. These results indicate that tRNS can enhance contrast sensitivity already after one training session, however this early onset is dependent on characteristics of the stimulus such as spatial frequency and orientation. In particular, the shallow depth of tRNS is likely to affect superficial layers of the visual cortex where neurons have higher preferred spatial frequencies than cells in further layers, while the lack of effect on vertical stimuli might reflect the optimization of the visual system to see cardinally oriented low contrast stimuli, leaving little room for short-term improvement. Taken together, these results suggest that online tRNS effects on visual perception are the result of a complex interaction between stimulus intensity and cortical anatomy, consistent with previous literature on brain stimulation.
METHODS:OBJECTIVE:There is growing interest in treating diseases by electrical stimulation and block of peripheral autonomic nerves, but a paucity of studies on excitation and block of small diameter autonomic axons. We conducted in vivo quantification of the strength-duration properties, activity-dependent slowing (ADS), and responses to kilohertz frequency (KHF) signals for the rat vagus nerve (VN). APPROACH:We conducted acute in vivo experiments in urethane-anesthetised rats. We placed two cuff electrodes on the left cervical VN and one cuff electrode on the anterior subdiaphragmatic VN. The rostral cervical cuff was used to deliver pulses to quantify recruitment and ADS. The caudal cervical cuff was used to deliver KHF signals. The subdiaphragmatic cuff was used to record compound action potentials (CAPs). MAIN RESULTS:We quantified the input-output recruitment and strength-duration curves. Fits to the data using standard strength-duration equations were qualitatively similar, but the resulting chronaxie and rheobase estimates varied substantially. We measured larger thresholds for the slowest fibres (0.5 to 1 m/s), especially at shorter pulse widths. Using a novel cross-correlation CAP-based analysis, we measured ADS of ~2.3% after 3 min of 2 Hz stimulation, which is comparable to ADS reported for sympathetic efferents in somatic nerves, but much smaller than ADS in cutaneous nociceptors. We found greater ADS with higher stimulation frequency and non-monotonic changes in CV in select cases. We found monotonically increasing block thresholds across frequencies from 10 to 80 kHz for both fast and slow fibres. Further, following 25 s of KHF signal, neural conduction could require tens of seconds to recover. SIGNIFICANCE:The quantification of mammalian autonomic nerve responses to conventional and KHF signals provides essential information for development of peripheral nerve stimulation therapies and for understanding their mechanisms of action.
METHODS:BACKGROUND:Early accounts of forced thought were reported at the onset of a focal seizure, and characterized as vague, repetitive, and involuntary intellectual auras distinct from perceptual or psychic hallucinations or illusions. Here, we examine the neural underpinnings involved in conceptual thought by presenting a series of 3 patients with epilepsy reporting intrusive thoughts during electrical stimulation of the left lateral prefrontal cortex (PFC) during invasive surgical evaluation. We illustrate the widespread networks involved through two independent brain imaging modalities: resting state functional magnetic resonance imaging (fMRI) (rs-fMRI) and task-based meta-analytic connectivity modeling (MACM). METHODS:We report the clinical and stimulation characteristics of three patients with left hemispheric language dominance who demonstrate forced thought with functional mapping. To examine the brain networks underlying this phenomenon, we used the regions of interest (ROI) centered at the active electrode pairs. We modeled functional networks using two approaches: (1) rs-fMRI functional connectivity analysis, representing 81 healthy controls and (2) meta-analytic connectivity modeling (MACM), representing 8260 healthy subjects. We also determined the overlapping regions between these three subjects' rs-fMRI and MACM networks through a conjunction analysis. RESULTS:We identified that left PFC was associated with a large-scale functional network including frontal, temporal, and parietal regions, a network that has been associated with multiple cognitive functions including semantics, speech, attention, working memory, and explicit memory. CONCLUSIONS:We illustrate the neural networks involved in conceptual thought through a unique patient population and argue that PFC supports this function through activation of a widespread network.