2026-11-092026-11-09https://scholars.csmu.edu.tw/handle/123456789/38563In female rats, contraction of the external urethral sphincter activates afferents that inhibit reflex bladder contractions; whereas infusion of fluid through the urethra facilitates bladder contractions. The bladder-to-urethra and urethra-to-bladder reflex have been explored well to demonstrate the mechanisms for the neural control of micturition. Both ionotropic N-methyl-D-aspartic acid (NMDA) and α-amino-3-hydroxy-5-methyl- 4-isoxazoleproprionate (AMPA) receptors are important in the micturition reflex pathway. In our previous study, we have established a pelvic-pudendal reflex plasticity (long-term potentiation-like reflex in the external urethral sphincter electromyogram activity) model in anesthetized rats. This pelvic-pudendal reflex mechanism has also been demonstrated to be mediated by glutamate, through ionotropic NMDA and AMPA receptors directly regulate the opening of ion channels to sodium, potassium and calcium ions via repetitive stimulation. In 2006, our study reveals that estrogen modulates the spinal NMDA mediated pelvic nerve-to-urethra reflex (PUR) plasticity in rats. However, influence of estrogen on micturition thresholds in the rat is also involved by the hypogastric nerve. Whether estrogen affect the neural pathway within the central nervous system (CNS), the efferent nerve innervating the urethra, or the striated urethral musculature need be further investigated to clarify the underlying mechanism involved in the changes in PUR reflex activity. Recently, some hypothesis support that estradiol may display as a hormone or even a neurotransmitter in the brain and spinal cord. The rapid regulation of CNS estrogen action may act on the transmembrane intracellular estrogen receptor (ER) through non-genomic pathway to conduct a rapid cell signaling. Rapid response of estrogen in the CNS is mediated by phosporylation of aramatase to modulate glutamatergic inputs. The deductive mechanisms of rapid responses of estrogen to modulate neuronal activity in a manner similar to the action of a neurotransmitter or neuromodulator as follows: ERα/β or novel membrane ER .. protein kinase A (PKA), protein kinase C (PKC), or mitogen-activated protein kinase (MAPK) .. cAMP-responsive element-binding protein (CREB) .. extracellular signal- regulated protein kinases (ERK) .. non-genomic effects or indirect genomic effects. In peripheral organ system, estrogen level has also been found to be able to influence on micturition thresholds on the female rat before and after bladder inflammation. In order to develop the working mechanisms of neuromodulation in the treatment of lower urinary tract dysfunction, in this study, we try to evaluate that 1. Whether estrogen modulates the spinal NMDA mediated PUR reflex potentiation may be affected by bilateral hypogastric neurectomy? Whether bilateral hypogastric neurectomy changes the external urethral sphincter electromyogram activity? 2. Whether estrogen is able to modulate PUR via transmembrane intracellular ER? 3. Roles and relationships of ERα/β, PKA, PKC, CREB, and ERK in the signaling pathway in PUR 4. Protein expression of PKA, PKC, CREB, and ERK in the dorsal horn of the spinal cord after repetitive stimulation on the pelvic nerve.由骨盆神經經脊髓再傳至會陰神經的反射路徑，被稱為骨盆神經-脊髓-外尿道括約肌反射 (pelvic-spinal- external urethral sphincter reflex)。 經由電刺激骨盆神經殘幹（遠端已截斷的骨盆神經）， 可在外尿道括約肌上的肌電圖 (Electromyogram) 記錄到反應，此一活動被稱為外尿道括約肌肌電圖活動性 (external urethral sphincter electromyogram activity, EUSE activity)。 我們的實驗室利用此一模式做為模擬由膀胱的感覺神經引發外尿道括約肌反應的試驗；更利用此一模式建立了類似在大腦和脊髓內已被廣泛研究的長期增益現象 (long-term potentiation， 或稱為反應塑性，reflex plasticity) 的脊髓反射增益作用現象 (spinal reflex potentiation, SRP)。 也驗證了此一反射路徑可透過NMDA和 AMPA接受器路徑的調控。 在2006年我們也發現：Estrogen可以透過NMDA的路徑調控骨盆神經-脊髓-外尿道括約肌的反射塑性(即調控脊髓反射增益現象)的效應；下腹神經所支配的尿道平滑肌是否有參與此一反射活動則未可知。 而Estrogen 在大腦及脊髓內的作用及產生作用的方式，是扮演神經傳導物質 (neurotransmitter) 或者是神經調控物質 (neuromodulator)， 最近屢被探討。 其反應路徑可能經由ERα/β → PKA, PKC, MAPK → CREB → ERK 引起 indirect genomic effect；也可能經由細胞膜的 non-genomic effect。 但它們的調控路徑則尚待進一步的研究去確立。 因此，我們擬進行本次為期三年的研究，以釐清下列問題： 1. 下腹神經有無參與Estrogen對於骨盆神經-脊髓-外尿道括約肌反射的調控？ 截斷下腹神經後，外尿道括約肌的反射增益現象的效應會增強或減弱？ 2. Estrogen是否會透過non-genomic effect 的快速反應調控骨盆神經-脊髓-外尿道括約肌反射增益現象？ 3. 進一步釐清在脊髓背角上PKA, PKC, CREB, ERK 參與調控路徑的上、下游關係；並以半定量的方法檢測它們在脊髓背角上的蛋白質的表現數量。Project