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Dwivedi R, Drumm BT, Alkawadri T, Martin SL, Sergeant GP, Hollywood MA, Thornbury KD. The TMEM16A blockers benzbromarone and MONNA cause intracellular Ca2+-release in mouse bronchial smooth muscle cells. Eur J Pharmacol 2023; 947:175677. [PMID: 36967079 DOI: 10.1016/j.ejphar.2023.175677] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/13/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023]
Abstract
We investigated effects of TMEM16A blockers benzbromarone, MONNA, CaCCinhA01 and Ani9 on isometric contractions in mouse bronchial rings and on intracellular calcium in isolated bronchial myocytes. Separate concentrations of carbachol (0.1-10 μM) were applied for 10 min periods to bronchial rings, producing concentration-dependent contractions that were well maintained throughout each application period. Benzbromarone (1 μM) markedly reduced the contractions with a more pronounced effect on their sustained component (at 10 min) compared to their initial component (at 2 min). Iberiotoxin (0.3 μM) enhanced the contractions, but they were still blocked by benzbromarone. MONNA (3 μM) and CaCCinhA01 (10 μM) had similar effects to benzbromarone, but were less potent. In contrast, Ani9 (10 μM) had no effect on carbachol-induced contractions. Confocal imaging revealed that benzbromarone (0.3 μM), MONNA (1 μM) and CaCCinhA01 (10 μM) increased intracellular calcium in isolated myocytes loaded with Fluo-4AM. In contrast, Ani9 (10 μM) had no effect on intracellular calcium. Benzbromarone and MONNA also increased calcium in calcium-free extracellular solution, but failed to do so when intracellular stores were discharged with caffeine (10 mM). Caffeine was unable to cause further discharge of the store when applied in the presence of benzbromarone. Ryanodine (100 μM) blocked the ability of benzbromarone (0.3 μM) to increase calcium, while tetracaine (100 μM) reversibly reduced the rise in calcium induced by benzbromarone. We conclude that benzbromarone and MONNA caused intracellular calcium release, probably by opening ryanodine receptors. Their ability to block carbachol contractions was likely due to this off-target effect.
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Lim XR, Bradley E, Griffin CS, Hollywood MA, Sergeant GP, Thornbury KD. Fast voltage-dependent sodium (Na V ) currents are functionally expressed in mouse corpus cavernosum smooth muscle cells. Br J Pharmacol 2021; 179:1082-1101. [PMID: 34767251 DOI: 10.1111/bph.15728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/17/2021] [Accepted: 10/19/2021] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Corpus cavernosum smooth muscle (CCSM) exhibits phasic contractions that are coordinated by ion channels. Mouse models are commonly used to study erectile dysfunction, but there are few published electrophysiological studies of mouse CCSM. We describe, for the first time, voltage-dependent sodium (NaV ) currents in mouse CCSM and investigate their function. EXPERIMENTAL APPROACH Electrophysiological, pharmacological, and immunocytochemical studies on isolated CCSM cells. Tension measurements in whole tissue. KEY RESULTS A fast, voltage-dependent sodium current was induced by depolarising steps. Steady-state activation and inactivation curves revealed a window current between -60 and -30 mV. Two populations of NaV currents, ('TTX-sensitive') and ('TTX-insensitive'), were distinguished. TTX-sensitive current showed 48% block with the NaV -subtype-specific blockers ICA-121431 (NaV 1.1-1.3), PF-05089771 (NaV 1.7), and 4,9-anhydro-TTX (NaV 1.6). TTX-insensitive current was insensitive to A803467, a NaV 1.8 blocker. Immunocytochemistry confirmed the expression of NaV 1.5 and NaV 1.4 in freshly dispersed CCSM cells. Veratridine, a NaV activator, reduced time-dependent inactivation of the current and increased the duration of evoked action potentials. Veratridine induced phasic contractions in CCSM strips. This effect was reversible with TTX and nifedipine but not by KB-R7943. CONCLUSION AND IMPLICATIONS We report, for the first time, a fast voltage-dependent sodium current in mouse CCSM. Stimulation of this current increases the contractility of corpus cavernosum in vitro, suggesting that it may contribute to the mechanisms of detumescence, and potentially serve as a clinically relevant target for pharmaceutical intervention in erectile dysfunction. Further work will be necessary to define its role.
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Affiliation(s)
| | | | | | | | | | - Keith D Thornbury
- Smooth Muscle Research Centre Dundalk Institute of Technology, Dublin, Ireland
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Hashimoto D, Hirashima T, Yamamura H, Kataoka T, Fujimoto K, Hyuga T, Yoshiki A, Kimura K, Kuroki S, Tachibana M, Suzuki K, Yamamoto N, Morioka S, Sasaki T, Yamada G. Dynamic erectile responses of a novel penile organ model utilizing TPEM†. Biol Reprod 2021; 104:875-886. [PMID: 33511393 DOI: 10.1093/biolre/ioab011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two-photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (Cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction-related genes, Hypoxia-inducible factor 1-alpha (Hif1a), glutathione peroxidase 1 (Gpx1), Ras homolog family member A (RhoA), and Rho-associated protein kinase (Rock), was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.
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Affiliation(s)
- Daiki Hashimoto
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Tsuyoshi Hirashima
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Hisao Yamamura
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Tomoya Kataoka
- Department of Clinical Pharmaceutics, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Kota Fujimoto
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Taiju Hyuga
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Atsushi Yoshiki
- Experimental Animal Division, RIKEN BioResource Research Center, Tsukuba, Ibaraki, Japan
| | - Kazunori Kimura
- Department of Clinical Pharmaceutics, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.,Department of Hospital Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Shunsuke Kuroki
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Makoto Tachibana
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Kentaro Suzuki
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
| | - Nobuhiko Yamamoto
- Cellular and Molecular Neurobiology Group, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Shin Morioka
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takehiko Sasaki
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Gen Yamada
- Department of Developmental Genetics, Institute of Advanced Medicine, Wakayama Medical University (WMU), Wakayama, Japan
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Drumm BT, Hennig GW, Baker SA, Sanders KM. Applications of Spatio-temporal Mapping and Particle Analysis Techniques to Quantify Intracellular Ca2+ Signaling In Situ. J Vis Exp 2019. [PMID: 30663707 DOI: 10.3791/58989] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Ca2+ imaging of isolated cells or specific types of cells within intact tissues often reveals complex patterns of Ca2+ signaling. This activity requires careful and in-depth analyses and quantification to capture as much information about the underlying events as possible. Spatial, temporal and intensity parameters intrinsic to Ca2+ signals such as frequency, duration, propagation, velocity and amplitude may provide some biological information required for intracellular signalling. High-resolution Ca2+ imaging typically results in the acquisition of large data files that are time consuming to process in terms of translating the imaging information into quantifiable data, and this process can be susceptible to human error and bias. Analysis of Ca2+ signals from cells in situ typically relies on simple intensity measurements from arbitrarily selected regions of interest (ROI) within a field of view (FOV). This approach ignores much of the important signaling information contained in the FOV. Thus, in order to maximize recovery of information from such high-resolution recordings obtained with Ca2+dyes or optogenetic Ca2+ imaging, appropriate spatial and temporal analysis of the Ca2+ signals is required. The protocols outlined in this paper will describe how a high volume of data can be obtained from Ca2+ imaging recordings to facilitate more complete analysis and quantification of Ca2+ signals recorded from cells using a combination of spatiotemporal map (STM)-based analysis and particle-based analysis. The protocols also describe how different patterns of Ca2+ signaling observed in different cell populations in situ can be analyzed appropriately. For illustration, the method will examine Ca2+ signaling in a specialized population of cells in the small intestine, interstitial cells of Cajal (ICC), using GECIs.
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Affiliation(s)
- Bernard T Drumm
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine;
| | - Grant W Hennig
- Department of Pharmacology, The Robert Larner, M.D. College of Medicine, University of Vermont
| | - Salah A Baker
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada Reno School of Medicine
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Thornbury KD, Hollywood MA, Sergeant GP. Ion Channels and Intracellular Calcium Signalling in Corpus Cavernosum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:171-194. [PMID: 31183827 DOI: 10.1007/978-981-13-5895-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The corpus cavernosum smooth muscle is important for both erection of the penis and for maintaining penile flaccidity. Most of the time, the smooth muscle cells are in a contracted state, which limits filling of the corpus sinuses with blood. Occasionally, however, they relax in a co-ordinated manner, allowing filling to occur. This results in an erection. When contractions of the corpus cavernosum are measured, it can be deduced that the muscle cells work together in a syncytium, for not only do they spontaneously contract in a co-ordinated manner, but they also synchronously relax. It is challenging to understand how they achieve this.In this review we will attempt to explain the activity of the corpus cavernosum, firstly by summarising current knowledge regarding the role of ion channels and how they influence tone, and secondly by presenting data on the intracellular Ca2+ signals that interact with the ion channels. We propose that spontaneous Ca2+ waves act as a primary event, driving transient depolarisation by activating Ca2+-activated Cl- channels. Depolarisation then facilitates Ca2+ influx via L-type voltage-dependent Ca2+ channels. We propose that the spontaneous Ca2+ oscillations depend on Ca2+ release from both ryanodine- and inositol trisphosphate (IP3)-sensitive stores and that modulation by signalling molecules is achieved mainly by interactions with the IP3-sensitive mechanism. This pacemaker mechanism is inhibited by nitric oxide (acting through cyclic GMP) and enhanced by noradrenaline. By understanding these mechanisms better, it might be possible to design new treatments for erectile dysfunction.
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Affiliation(s)
- Keith D Thornbury
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland.
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Regional Development Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, Ireland
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Hannigan KI, Griffin CS, Large RJ, Sergeant GP, Hollywood MA, McHale NG, Thornbury KD. The role of Ca 2+-activated Cl - current in tone generation in the rabbit corpus cavernosum. Am J Physiol Cell Physiol 2017; 313:C475-C486. [PMID: 28835432 DOI: 10.1152/ajpcell.00025.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 08/03/2017] [Accepted: 08/09/2017] [Indexed: 11/22/2022]
Abstract
Rabbit corpus cavernosum smooth muscle (RCCSM) cells express ion channels that produce Ca2+-activated Cl- (IClCa) current, but low sensitivity to conventional antagonists has made its role in tone generation difficult to evaluate. We have reexamined this question using two new generation IClCa blockers, T16Ainh-A01 and CaCCinh-A01. Isolated RCCSM cells were studied using the perforated patch method. Current-voltage protocols revealed that both L-type Ca2+ current and IClCa T16Ainh-A01 and CaCCinh-A01 (10 μM) reduced IClCa by ~85%, while 30 μM abolished it. L-type Ca2+ current was unaffected by 10 μM CaCCinh-A01 but was reduced by 50% at 30 μM CaCCinh-A01, 46% at 10 μM T16Ainh-A01, and 78% at 30 μM T16Ainh-A01. Both drugs reduced spontaneous isometric tension in RCCSM strips, by 60-70% at 10 μM and >90% at 30 μM. Phenylephrine (PE)-enhanced tension was also reduced (ED50 = 3 μM, CaCCinh-A01; 14 μM, T16Ainh-A01). CaCCinh-A01 at 10 μM had little effect on 60 mM KCl contractures, though they were reduced by 30 μM CaCCinh-A01 and T16Ainh-A01 (10 μM and 30 μM) consistent with their effects on L-type Ca2+ current. Both drugs also reversed the stimulatory effect of PE on intracellular Ca2+ waves, studied with laser scanning confocal microscopy in isolated RCCSM cells. In conclusion, although both drugs were effective blockers of IClCa, the effect of T16Ainh-A01 on L-type Ca2+ current precludes its use for evaluating the role of IClCa in tone generation. However, 10 μM CaCCinh-A01 selectively blocked IClCa versus L-type Ca2+ current and reduced spontaneous and PE-induced tone, suggesting that IClCa is important in maintaining penile detumescence.
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Affiliation(s)
- Karen I Hannigan
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Caoimhin S Griffin
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Roddy J Large
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Noel G McHale
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
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7
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Hannigan KI, Large RJ, Bradley E, Hollywood MA, Sergeant GP, McHale NG, Thornbury KD. Effect of a novel BKCa opener on BKCa currents and contractility of the rabbit corpus cavernosum. Am J Physiol Cell Physiol 2016; 310:C284-92. [DOI: 10.1152/ajpcell.00273.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/23/2015] [Indexed: 11/22/2022]
Abstract
Large-conductance Ca2+-activated K+ (BKCa) channels are thought to play a key role in the regulation of corpus cavernosum smooth muscle (CCSM) excitability. Few BKCa channel openers have been accepted for clinical development. The effect of the novel BKCa channel opener GoSlo-SR5-130 on electrical activity in isolated rabbit CCSM cells and mechanical activity in strips of rabbit CCSM was examined. Single-channel currents were observed in inside-out patches. These channels were sensitive to Ca2+, blocked by penitrem A, and had a conductance of 291 ± 20 pS ( n = 7). In the presence of GoSlo-SR5-130, the number of open BKCa channels increased. Using voltage-ramp protocols, GoSlo-SR5-130 caused currents to activate at more negative potentials in a concentration-dependent manner, shifting the half-maximal activation voltage potential to the left on the voltage axis. Therefore, BKCa channels were open within the physiological range of membrane potentials in the presence of GoSlo-SR5-130. GoSlo-SR5-130 also resulted in an increase in the activity of spontaneous transient outward currents in myocytes isolated from CCSM, and this effect was reversed by iberiotoxin. In current-clamp mode, GoSlo-SR5-130 hyperpolarized the cell membrane. Isometric tension recording of strips of rabbit corpus cavernosum showed that GoSlo-SR5-130 inhibited spontaneous contractions in a concentration-dependent manner. This effect was reversed in the presence of iberiotoxin, suggesting that GoSlo-SR5-130 exerts its effect through BKCa channels. These findings suggest that GoSlo-SR5-130 is an effective tool for the study of BKCa channels and that these channels can modulate CCSM activity and are possible targets for the treatment of erectile dysfunction.
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Affiliation(s)
- K. I. Hannigan
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - R. J. Large
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - E. Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - M. A. Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - G. P. Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - N. G. McHale
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - K. D. Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
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Doyle C, Sergeant GP, Hollywood MA, McHale NG, Thornbury KD. Effects of Phenylephrine on Spontaneous Activity and L‐Type Ca2+ Current in Isolated Corpus Cavernosum Myocytes. J Sex Med 2012; 9:2795-805. [DOI: 10.1111/j.1743-6109.2012.02847.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Calcium-activated chloride channels in the corpus cavernosum: recent developments and future of a key cellular component of the erectile process. Int J Impot Res 2012; 24:211-6. [PMID: 22717765 DOI: 10.1038/ijir.2012.22] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Calcium-activated chloride channels (CaCCs) are one of five families of chloride channels, ubiquitously expressed, and essential for a host of biological actions. CaCCs have key roles in processes as diverse as olfactory transduction and epithelial secretion, and also CaCCs are essential in smooth muscle contraction. The corpus cavernosum is a vascular smooth muscle that must relax to facilitate erections. Parasympathetic activation produces relaxation of the corpus cavernosum through a nitric oxide-dependent pathway, and sympathetic stimulation in both preventing and terminating erections by contracting the corpus cavernosum. Both these pathways affect activity of CaCCs. The past 5 years produced many successes in CaCC research. One key area of success was the identification of the elusive 'molecular candidate' of CaCCs, as the TMEM16A protein (dubbed anoctamin-1) and potentially other members of the anoctamin family of transmembrane proteins. However, enthusiasm has been somewhat tempered because of evidence that this family of proteins may not be responsible for calcium-activated chloride currents in certain epithelial tissues. Several studies identified specific inhibitors of CaCCs as well as specific inhibitors for anoctamin-1. Despite the number of recent achievements in this field there are many details that still need to be elucidated. Of particular value would be more details on the identity of the CaCCs in corpus cavernosum smooth muscle, using new inhibitors to gain insight into the signalling pathway, and the evaluation of whether inhibition of CaCCs provides any specific benefit in different models of ED.
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Andersson KE. Mechanisms of penile erection and basis for pharmacological treatment of erectile dysfunction. Pharmacol Rev 2011; 63:811-59. [PMID: 21880989 DOI: 10.1124/pr.111.004515] [Citation(s) in RCA: 234] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Erection is basically a spinal reflex that can be initiated by recruitment of penile afferents, both autonomic and somatic, and supraspinal influences from visual, olfactory, and imaginary stimuli. Several central transmitters are involved in the erectile control. Dopamine, acetylcholine, nitric oxide (NO), and peptides, such as oxytocin and adrenocorticotropin/α-melanocyte-stimulating hormone, have a facilitatory role, whereas serotonin may be either facilitatory or inhibitory, and enkephalins are inhibitory. The balance between contractant and relaxant factors controls the degree of contraction of the smooth muscle of the corpora cavernosa (CC) and determines the functional state of the penis. Noradrenaline contracts both CC and penile vessels via stimulation of α₁-adrenoceptors. Neurogenic NO is considered the most important factor for relaxation of penile vessels and CC. The role of other mediators, released from nerves or endothelium, has not been definitely established. Erectile dysfunction (ED), defined as the "inability to achieve or maintain an erection adequate for sexual satisfaction," may have multiple causes and can be classified as psychogenic, vasculogenic or organic, neurologic, and endocrinologic. Many patients with ED respond well to the pharmacological treatments that are currently available, but there are still groups of patients in whom the response is unsatisfactory. The drugs used are able to substitute, partially or completely, the malfunctioning endogenous mechanisms that control penile erection. Most drugs have a direct action on penile tissue facilitating penile smooth muscle relaxation, including oral phosphodiesterase inhibitors and intracavernosal injections of prostaglandin E₁. Irrespective of the underlying cause, these drugs are effective in the majority of cases. Drugs with a central site of action have so far not been very successful. There is a need for therapeutic alternatives. This requires identification of new therapeutic targets and design of new approaches. Research in the field is expanding, and several promising new targets for future drugs have been identified.
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Affiliation(s)
- K-E Andersson
- Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine, Medical Center Boulevard, Winston Salem, NC 27157, USA.
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11
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Zhao C, Cho KW, Park JK. Three phases of corporal tracing elicited by electrical field stimulation on rabbit corpus cavernosum smooth muscle in penile perfusion model. J Sex Med 2011; 8:1039-47. [PMID: 21235727 DOI: 10.1111/j.1743-6109.2010.02178.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Nitric oxide (NO) has been shown to mediate electrical field stimulation (EFS)-caused smooth muscle relaxation. It is known that the neural control of penile erection involves adrenergic, cholinergic, and non-adrenergic-non-cholinergic (NANC) neuro-effector systems; however, the effects of EFS on adrenergic and cholinergic nerves are not clear. AIMS To elucidate EFS-induced signal transductions involved in adrenergic, cholinergic, and NANC neuro-effector systems by using an in vitro penile perfusion model. METHODS EFS was performed on penile corpus cavernosum smooth muscle from male New Zealand White rabbits, which was pre-contracted with L-phenylephrine (10 µM). We investigated the penile tracing elicited by EFS on tissues pre-incubated with guanethidine (Guan, 50 µM), tetrodotoxin (TTX, 10 µM), Nω nitro-L-arginine-methyl ester (L-NAME, 1 mM), atropine (50 µM), or eserine (10 µM). MAIN OUTCOME MEASURES The time-to-peak of each phase, the percentage of relaxation, and the area under the curve (AUC). RESULTS We discovered an extraordinary phenomenon: three distinct phases elicited by EFS. Phase I was abolished by L-NAME. Phase II was decreased by eserine and Guan, but increased by L-NAME. Phase III was abolished by atropine, but enhanced by eserine and Guan. TTX diminished all three phases. The time to reach the top of phase I was delayed by TTX. The time to attain the peak of phase II was shortened by L-NAME, but delayed by TTX and atropine. The time to reach the top of phase III was shortened by L-NAME, eserine, and Guan. AUC was significantly decreased by L-NAME and TTX. CONCLUSIONS EFS stimulated adrenergic, cholinergic, and NANC neuro-effector systems simultaneously. Phase I was related to the NO pathway. Phase II was multiply affected by self-recovery properties, and adrenergic and cholinergic nerves. Phase III was related to cholinergic nerves. The corporal tracing elicited by EFS was the balanced result of multiple factors.
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Affiliation(s)
- Chen Zhao
- Department of Urology, Medical School, and Institute for Medical Sciences, Chonbuk National University, and Research Institute and CTC for Medical Device of Chonbuk National University Hospital, Jeonju, Korea
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McCarron JG, Chalmers S, MacMillan D, Olson ML. Agonist-evoked Ca(2+) wave progression requires Ca(2+) and IP(3). J Cell Physiol 2010; 224:334-44. [PMID: 20432430 PMCID: PMC3947531 DOI: 10.1002/jcp.22103] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Smooth muscle responds to IP(3)-generating agonists by producing Ca(2+) waves. Here, the mechanism of wave progression has been investigated in voltage-clamped single smooth muscle cells using localized photolysis of caged IP(3) and the caged Ca(2+) buffer diazo-2. Waves, evoked by the IP(3)-generating agonist carbachol (CCh), initiated as a uniform rise in cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) over a single though substantial length (approximately 30 microm) of the cell. During regenerative propagation, the wave-front was about 1/3 the length (approximately 9 microm) of the initiation site. The wave-front progressed at a relatively constant velocity although amplitude varied through the cell; differences in sensitivity to IP(3) may explain the amplitude changes. Ca(2+) was required for IP(3)-mediated wave progression to occur. Increasing the Ca(2+) buffer capacity in a small (2 microm) region immediately in front of a CCh-evoked Ca(2+) wave halted progression at the site. However, the wave front does not progress by Ca(2+)-dependent positive feedback alone. In support, colliding [Ca(2+)](c) increases from locally released IP(3) did not annihilate but approximately doubled in amplitude. This result suggests that local IP(3)-evoked [Ca(2+)](c) increases diffused passively. Failure of local increases in IP(3) to evoke waves appears to arise from the restricted nature of the IP(3) increase. When IP(3) was elevated throughout the cell, a localized increase in Ca(2+) now propagated as a wave. Together, these results suggest that waves initiate over a surprisingly large length of the cell and that both IP(3) and Ca(2+) are required for active propagation of the wave front to occur.
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Affiliation(s)
- John G McCarron
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, John Arbuthnott Building, Glasgow, UK.
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13
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Zhao C, Chae HJ, Kim SH, Cui WS, Lee SW, Jeon JH, Park JK. A new perfusion model for studying erectile function. J Sex Med 2010; 7:1419-28. [PMID: 20059654 DOI: 10.1111/j.1743-6109.2009.01652.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
INTRODUCTION The present study introduces a newly devised in vitro penile perfusion model, which allows the measurement of changes in intracavernosum pressure (ICP), tension, and cyclic nucleotides in penile tissue in a one-step procedure. AIMS We compared the penile perfusion model with the classical penile strip chamber model to develop the new model. METHODS We investigated the role of nitric oxide-cyclic guanosine monophosphate pathway in both systems activated by acetylcholine or electrical field stimulation (EFS). We measured cGMP (cyclic guanosine monophosphate) in the penile corpus cavernosum smooth muscle in both systems and perfusates in the penile perfusion model. We determined ICP, tension, and cGMP simultaneously in penile perfusion model during the experiments. MAIN OUTCOME MEASURES Changes of tension and cGMP in both models, and of cGMP in perfusates and of ICP in penile perfusion model. RESULTS In both systems, acetylcholine relaxed the phenylephrine-precontracted penile corpus cavernosum smooth muscle in a concentration-dependent manner. EFS decreased the tension in both models and ICP in the penile perfusion model in a frequency-dependent manner. Pretreatment with atropine, Nomega nitro-L-arginine-methyl ester (L-NAME), and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) blocked the acetylcholine-induced decrease in the tension in both models and ICP in penile perfusion model. Acetylcholine increased cGMP levels in the perfusate of penile perfusion model and the changes were attenuated by tetrodotoxin (TTX), atropine, L-NAME and ODQ. EFS increased cGMP levels of the penile corpus cavernosum smooth muscle of both models and the changes were attenuated by TTX, atropine, L-NAME, and ODQ. CONCLUSION The results indicated that the responses of penile strip and perfused penile tissue to acetylcholine and EFS were very similar in both models in terms of tension and cGMP levels. Furthermore, the new model has more advantages over the classical penile strip chamber model in measuring intracavernosum metabolic changes and ICP without interruption of the procedure.
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Affiliation(s)
- Chen Zhao
- Department of Urology, Medical School, and Institute for Medical Sciences, Chonbuk National University, and Research Institute of Clinical Medicine and CTC for Medical Device of Chonbuk National University Hospital, Jeonju 561-712, Korea
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McCloskey C, Cagney V, Large R, Hollywood M, Sergeant G, McHale N, Thornbury K. Voltage‐dependent Ca2+ Currents Contribute to Spontaneous Ca2+ Waves in Rabbit Corpus Cavernosum Myocytes. J Sex Med 2009; 6:3019-31. [DOI: 10.1111/j.1743-6109.2009.01451.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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