Effect of Alpha 1-Adrnoceptor Antagonists on Postsynaptic Sensitivity in Substantia Gelatinosa Neurons From Lumbosacral Spinal Cord in Rats Using Slice Patch-Clamp Technique for mEPSC

Developing a Novel Method for the Analysis of Spinal Cord-Penile Neurotransmission Mechanisms

Sexual dysfunction can be caused by impaired neurotransmission from the peripheral to the central nervous system. Therefore, it is important to evaluate the input of sensory information from the peripheral genital area and investigate the control mechanisms in the spinal cord to clarify the pathological basis of sensory abnormalities in the genital area. However, an in vivo evaluation system for the spinal cord-penile neurotransmission mechanism has not yet been developed. Here, urethane-anesthetized rats were used to evaluate neuronal firing induced by innocuous or nociceptive stimulation of the penis using extracellular recording or patch-clamp techniques in the lumbosacral spinal dorsal horn and electrophysiological evaluation in the peripheral pelvic nerves. As a result, innocuous and nociceptive stimuli-evoked neuronal firing was successfully recorded in the deep and superficial spinal dorsal horns, respectively. The innocuous stimuli-evoked nerve firing was also recorded in the pelvic nerve. These firings were suppressed by lidocaine. To the best of our knowledge, this is the first report of a successful quantitative evaluation of penile stimuli-evoked neuronal firing. This method is not only useful for analyzing the pathological basis of spinal cord-penile neurotransmission in sexual dysfunction but also provides a useful evaluation system in the search for new treatments.

The Selective α1 Antagonist Tamsulosin Alters ECM Distributions and Cellular Metabolic Functions of ARPE 19 Cells in a Concentration-Dependent Manner

The purpose of the present study was to examine the effect of the selective α1 antagonist tamsulosin (TAM) on human retinal pigment epithelium cells, ARPE 19. Two-dimension (2D) and three-dimension (3D) cultured ARPE 19 cells were used in the following characterizations: (1) ultrastructure by scanning electron microscopy (SEM) (2D); (2) barrier functions by transepithelial electrical resistance (TEER) measurements, and FITC-dextran permeability (2D); (3) real time cellular metabolisms by Seahorse Bioanalyzer (2D); (4) physical properties, size and stiffness measurements (3D); and (5) expression of extracellular matrix (ECM) proteins, including collagen1 (COL1), COL4, COL6 and fibronectin (FN) by qPCR and immunohistochemistry (2D and 3D). TAM induced significant effects including: (1) alteration of the localization of the ECM deposits; (2) increase and decrease of the TEER values and FITC-dextran permeability, respectively; (3) energy shift from glycolysis into mitochondrial oxidative phosphorylation (OXPHOS); (4) large and stiffened 3D spheroids; and (5) down-regulations of the mRNA expressions and immune labeling of most ECM proteins in a concentration-dependent manner. However, in some ECM proteins, COL1 and COL6, their immunolabeling intensities were increased at the lowest concentration (1 μM) of TAM. Such a discrepancy between the gene expressions and immunolabeling of ECM proteins may support alterations of ECM localizations as observed by SEM. The findings reported herein indicate that the selective α1 antagonist, TAM, significantly influenced ECM production and distribution as well as cellular metabolism levels in a concentration-dependent manner.

Sophisticated regulation of micturition: review of basic neurourology

The neurological regulation of the lower urinary tract can be viewed separately from the perspective of sensory neurons and motor neurons. First, in the receptors of the bladder and urethra of sensory nerves, sensations are transmitted through the periaqueductal gray matter of the midbrain to the cerebral cortex, and the cerebrum goes through the process of decision-making. Motor neurons are divided into upper motor neurons (UMNs) and lower motor neurons (LMNs). UMNs coordinate storage and micturition in the brain stem so that synergic voiding can occur. LMNs facilitate muscle contractions in the spinal cord. The muscles involved in urinary storage and micturition are innervated by the somatic branches of sympathetic, parasympathetic, and peripheral nerves. Sympathetic nerves are responsible for contractions of urethral smooth muscles, while parasympathetic nerves originate from S2–S4 and are in charge of contractions of the bladder muscle. Somatic nerves originate from the motor neurons in Onuf’s nucleus, which is a specific part of somatic nerves. In this review, we will investigate the structures of the nervous systems related to the lower urinary tract and the regulatory system of innervation for the urinary storage and micturition and discuss the clinical significance and future prospects of neurourological research.

Analyses of the Mode of Action of an Alpha-Adrenoceptor Blocker in Substantia Gelatinosa Neurons in Rats

To elucidate why naftopidil increases the frequency of spontaneous synaptic currents in only some substantia gelatinosa (SG) neurons, post-hoc analyses were performed. Blind patch-clamp recording was performed using slice preparations of SG neurons from the spinal cords of adult rats. Spontaneous inhibitory and excitatory postsynaptic currents (sIPSCs and sEPSCs, respectively) were recorded. The ratios of the frequency and amplitude of the sIPSCs and sEPSCs following the introduction of naftopidil compared with baseline, and after the application of naftopidil, serotonin (5-HT), and prazosin, compared with noradrenaline (NA) were evaluated. First, the sIPSC analysis indicated that SG neurons reached their full response ratio for NA at 50 μM. Second, they responded to 5-HT (50 μM) with a response ratio similar to that for NA, but prazosin (10 μM) did not change the sEPSCs and sIPSCs. Third, the highest concentration of naftopidil (100 μM) led to two types of response in the SG neurons, which corresponded with the reactions to 5-HT and prazosin. These results indicate that not all neurons were necessarily activated by naftopidil, and that the micturition reflex may be regulated in a sophisticated manner by inhibitory mechanisms in these interneurons.