Onychopapilloma: its clinical, dermoscopic and pathologic features.

BACKGROUND: Onychopapilloma is a benign tumour of the nail bed and distal matrix and commonly presents as longitudinal erythronychia, longitudinal leukonychia or longitudinal melanonychia. Because onychopapilloma is rare, its clinical characteristics and dermoscopic findings have not been well investigated in Asia. OBJECTIVES: This study aimed to investigate the clinical characteristics and dermoscopic and pathologic findings of onychopapilloma in Korea. METHODS: We retrospectively reviewed the medical records and clinical/dermoscopic photographs of 39 patients diagnosed with onychopapilloma in the Pusan National University Hospitals (Busan and Yangsan) for 11 years (2010-2021). RESULTS: Among 39 patients, 23 (59.0%) were men, and 16 (41.0%) were women. The mean age was 46.1 (16-77) years. All lesions were single, and most of them were located on the fingers (92.3%), especially the thumb (66.7%). The most common clinical feature was longitudinal erythronychia (56.4%), and the most common dermoscopic finding was distal subungual hyperkeratosis (100%). We found two new dermoscopic features: macrolunula and trailing lunula along the longitudinal band. Among 18 patients who underwent surgical excision, only 6 (33.3%) showed typical acanthosis and papillomatosis on the nail bed. CONCLUSIONS: We found that Asian onychopapilloma has similar clinicodermoscopic findings to the Caucasian one, that is to say, longitudinal erythronychia and distal subungual hyperkeratosis were the most common nail change and dermoscopic finding, respectively. We propose two new dermoscopic features of onychopapilloma: macrolunula and trailing lunula along the longitudinal band.

Solar optics-based active panel for solar energy storage and disinfection of greywater.

Smart city and innovative building strategies are becoming increasingly more necessary because advancing a sustainable building system is regarded as a promising solution to overcome the depleting water and energy. However, current sustainable building systems mainly focus on energy saving and miss a holistic integration of water regeneration and energy generation. Here, we present a theoretical study of a solar optics-based active panel (SOAP) that enables both solar energy storage and photothermal disinfection of greywater simultaneously. Solar collector efficiency of energy storage and disinfection rate of greywater have been investigated. Due to the light focusing by microlens, the solar collector efficiency is enhanced from 25% to 65%, compared to that without the microlens. The simulation of greywater sterilization shows that 100% disinfection can be accomplished by our SOAP for different types of bacteria including Escherichia coli. Numerical simulation reveals that our SOAP as a lab-on-a-wall system can resolve the water and energy problem in future sustainable building systems.

Approach to Management of Eyes with no Light Perception after Open Globe Injury.

Loss of light perception (LP) after open globe injury (OGI) does not necessarily mean the patient will have permanent complete visual loss. Findings that seem to be associated reliably with permanent profound vision loss after OGI include optic nerve avulsion, optic nerve transection, and profound loss of intraocular contents, which can be identified with CT/MRI imaging albeit with varying degrees of confidence. Eyes with NLP after OGI that undergo successful primary repair with intact optic nerves may be considered for additional surgery, particularly if there is: (1) recovery of LP on the first day after primary repair; (2) treatable pathology underlying NLP status (e.g., extensive choroidal hemorrhage, dense vitreous and subretinal hemorrhage); (3) NLP in the fellow eye. We counsel patients that the chance of recovering ambulatory vision under these circumstances is very low (~5%).

Apolipoprotein B: novel indicator of elevated intraocular pressure.

PURPOSE: Many studies have reported associations between elevated intraocular pressure (IOP) and systemic health parameters, which suggest a common mechanism links IOP elevation and various related cardiometabolic risk factors. Furthermore, according to a recent study, serum apolipoprotein B (APO B) level is a predictor of coronary artery disease. This study was undertaken to analyse the relationship between serum apolipoprotein levels and IOP. METHODS: Healthy people (28,852) who attended a community hospital for a health checkup between January 2011 and December 2013 were enroled in the study. We measured age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), serum levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and apolipoprotein A1 (APO A1) and APO B, APO B/APO A1 ratios, and IOP. RESULTS: Univariate regression analysis showed IOP was positively correlated with BMI, SBP, DBP, TC, LDL-C, TG, APO B, and APO B/APO A1 (P<0.001), and negatively correlated with HDL-C (P<0.001). On the other hand, multivariate regression analysis adjusted for age, BMI, SBP, and DBP, revealed IOP was positive correlated with TC, TG, LDL-C, APO B, and APO B/APO A1, and negatively correlated with HDL-C (all <0.05). CONCLUSIONS: Among the various lipid profiles investigated, APO B was found to be most strongly correlated with IOP, regardless of sex. Additional studies are required to confirm the validity of apolipoprotein level as an index for predicting IOP.

Genetic analysis of seed-shattering genes in rice using an F3:4 population derived from an Oryza sativa x Oryza rufipogon cross.

Seed shattering of wild plant species is thought to be an adaptive trait to facilitate seed dispersal. For rice breeding, seed shatter-ing is an important trait for improving breeding strategies, particularly when developing lines use interspecific hybrids and introgression of genes from wild species. We developed F3:4 recombinant inbred lines from an interspecific cross between Oryza sativa cv. Ilpoombyeo and Oryza rufipogon. In this study, we genetically analyzed known shat-tering-related loci using the F3:4 population of O. sativa/O. rufipogon. CACTA-AG190 was significantly associated with the shattering trait CACTA-TD according to bulked segregant analysis results, and was found in the qSH-1 region of chromosome 1. Fine genetic mapping of the flanking regions around qSH-1 based on CACTA-AG190 revealed multiple-sequence variations. The highest limit of detection based on quantitative trait locus analysis was observed between shaap-7715 and a 518-bp insertion site. Two other quantitative trait locus analyses of seed-shattering-related loci, qSH-4 and sh-h, were performed using simple sequence repeat and allele-pecific single nucleotide polymor-phism markers. Our results can be applied for rice-breeding research, such as marker-assisted selection between cultivated and wild rice.

Regulated expression of neuronal SIRT1 and related genes by aging and neuronal ß2-containing nicotinic cholinergic receptors.

Longevity genes attenuate the aging process, but their expression in the brain during aging remains unknown. Loss of the majority of heteromeric brain nicotinic acetylcholine receptors (nAChRs) results in premature brain aging, and altered regulation of longevity genes could be involved. Using in situ hybridization, the expression of SIRT1, Ku70, Nampt, p53, forkhead Box O3 (FoxO3), and mitochondria uncoupling protein 5 (UCP5) was determined in neocortex and hippocampus of young adult 3-month and middle-aged 18-month-old wild-type (WT), and age-matched mice lacking ß2* heteromeric nAChRs (ß2-/-). Age-related structural changes were detected in WT mice. In particular, cortical thickness was decreased but neuronal density increased, and hippocampal volume increased with age. In contrast, young ß2-/- mice exhibited increased cortical neuronal density, and with age, cortical thickness decreased more dramatically, and hippocampal volume did not increase. Thus, young ß2-/- mice exhibited cortical signs of aging, and aging was accelerated at 18 months. The longevity genes probed exhibited similar expression patterns in frontal brain structures, with strong expression in hippocampus, medial habenula (MHb), and cortex. In WT mice, age significantly decreased expression of all genes except SIRT1 in cortical structures, and a similar pattern was detected in the MHb. Genotype had no effect on expression in young adults in either cortex or MHb, but increased mRNA expression of SIRT1, Nampt, and Ku70 was detected in cortex, hippocampus, and MHb of aged ß2-/- mice compared with WT mice. This is the first study to determine age-related expression of survival genes in forebrain areas. Although, structural changes indicative of accelerated aging are evident in young ß2-/- mice, the data suggest that nAChRs do not directly regulate expression of survival genes. However, loss of ß2* nAChRs could result in augmented cellular stress, which indirectly increases expression of SIRT1, Nampt, and Ku70 as an adaptive response to provide protection against neurodegeneration.

Expression of nicotinic acetylcholine receptors and subunit messenger RNAs in the enteric nervous system of the neonatal rat.

In the enteric nervous system (ENS) excitatory nicotinic cholinergic transmission is mediated by neuronal nicotinic acetylcholine receptors (nAChR) and is critical for the regulation of gastric motility. nAChRs are ligand-gated pentameric ion channels found in the CNS and peripheral nervous system. The expression of heteromeric nAChR and receptor subunit mRNAs was investigated in the neonatal rat ENS using receptor autoradiography with the radiolabeled ligand (125)I-epibatidine, and in situ hybridization with subtype specific probes for ligand binding alpha (alpha2, alpha3, alpha4, alpha5, alpha6) and structural beta (beta2, beta3, beta4) subunits. The results showed strong nicotine sensitive binding of (125)I-epibatidine around the stomach, and small and large intestines. The binding was partially displaced by A85380, a nicotinic ligand which differentiates between different heteromeric nAChR subtypes, suggesting a mixed receptor population. Radioactive in situ hybridization detected expression of alpha3, alpha5, alpha7, beta2 and beta4 mRNA in the myenteric plexus of the stomach, and small and large intestines. In the submucosal plexus of the small and large intestines expression of alpha3, alpha5 and beta4 was found in some ganglia. There was no signal for alpha4, alpha6 and beta3 in the ENS but positive hybridization signal for alpha2 transcripts was seen in some areas of the small intestines. However, the signal was not associated with any ganglion cells. The results confirm the presence of heteromeric nAChRs in the ENS similar to those found in the peripheral nervous system, with the majority being composed of alpha3(alpha5)beta4, and a few alpha3beta2 nAChRs. In addition, homomeric alpha7 nAChRs could be present.

Acute nicotine activates c-fos and activity-regulated cytoskeletal associated protein mRNA expression in limbic brain areas involved in the central stress-response in rat pups during a period of hypo-responsiveness to stress.

In adult rats, acute nicotine, the major psychoactive ingredient in tobacco smoke, stimulates the hypothalamic-pituitary-adrenal axis (HPA), resulting in activation of brain areas involved in stress and anxiety-linked behavior. However, in rat pups the first two postnatal weeks are characterized by hypo-responsiveness to stress, also called the 'stress non-responsive period' (SNRP). Therefore, we wanted to address the question if acute nicotine stimulates areas involved in the stress response during SNRP. To determine neuronal activation, the expression of the immediate-early genes c-fos and activity-regulated cytoskeletal associated protein (Arc) was studied in the central nucleus of the amygdala (CeA), bed nucleus stria terminalis (BST) and paraventricular hypothalamic nucleus (PVN), which are areas involved in the neuroendocrine and central stress response. Rat pups received nicotine tartrate (2 mg/kg) or saline by i.p. injection at postnatal days (P) 5, 7 and 10 and their brains were removed after 30 min. We used semi-quantitative radioactive in situ hybridization with gene specific antisense cRNA probes in coronal sections. In control pups, c-fos expression was low in most brain regions, but robust Arc hybridization was found in several areas including cingulate cortex, hippocampus and caudate. Acute nicotine resulted in significant induction of c-fos expression in the PVN and CeA at P5, P7 and P10, and in the BST at P7 and P10. Acute nicotine significantly induced expression of Arc in CeA at P5, P7 and P10, and in the BST at P10. In conclusion, acute nicotine age dependently activated different brain areas of the HPA axis during the SNRP. After P7, the response was more pronounced and included the BST, suggesting differential maturation of the HPA axis in response to nicotine.

Chronic headache after cranio-cervical trauma--hypothetical pathomechanism based upon neuroanatomical considerations.

BACKGROUND: Chronic headache after whiplash injury is common, but the underlying mechanisms have not yet been elucidated. On the basis of human neuroanatomy, we hypothesize that rear-end collision can cause leakage of the cerebrospinal fluid (CSF) into the epidural space most frequently at the lumbosacral level, inducing chronic headache. METHODS: We considered that the following phenomena would be evident in patients with chronic headache after rear-end collision: (1) orthostatic headache with early onset and long duration, (2) low intracranial pressure (ICP =or< 60 mm H2O), (3) CSF leakage mainly in the lumbosacral region on radioisotope-myelocisternography, and (4) diffuse pachymeningeal enhancement (DPE) on gadolinium enhanced magnetic resonant image (Gd-MRI). The clinical signs and symptoms, ICP and neuroimaging findings were analyzed retrospectively in 20 patients who complained of chronic headache after rear-end collisions. RESULTS: Headaches were orthostatic and started on the day of the accident in 14 patients. The headaches lasted more than 3 months in all patients. Mean ICP was 120 +/- 30 cm H2O. Only one patient showed low ICP. RI-myelocisternography revealed signs of CSF leakage at the lumbosacral level in 10 patients. Gd-MRI showed no abnormalities known to be characteristic of spontaneous intracranial hypotension (SIH). Chronic headache disappeared or was diminished in all patients by epidural blood patching in the lumbosacral region. CONCLUSION: This clinical study partly supports the validity of our verifiable hypothetical mechanism. The ICP is not low and DPE is not observed on Gd-MRI. Therefore, CSF leakage into the epidural space may not occur, but spinal CSF absorption may be over-activated. This condition may represent a new clinical entity.

Acetylcholine causes an increase of intracellular calcium in human sperm.

Sperm nicotinic acetylcholine receptors (nAChRs) can influence motility and the initiation of acrosome reaction (AR). We report that AR initiation by acetylcholine (ACh) in capacitated human sperm requires both Na+ and Ca2+ in the external medium. Pre-incubation with 50 microM 3-quinuclidinyl benzilate (QNB) or 50 nM strychnine failed to inhibit the ACh-initiated AR, demonstrating that muscarinic AChRs and nAChRs containing alpha9 subunits do not mediate this event. Choline (2.5, 5 and 10 mM), a highly specific but low potency agonist of the alpha7 nAChR initiated AR, with its effect blocked by the nAChR antagonist methyllycaconitine (MLA). ACh (50-400 microM) stimulated a small transient rise in the intracellular Ca2+ in sperm populations loaded with FURA-2, with 200 microM ACh being maximal (146 nM +/- 23 SEM). The nAChR antagonists, alpha-bungarotoxin (alpha-BTX) and MLA, reduced the ACh-initiated Ca2+ rise by 75 and 78%, respectively, demonstrating the majority of the rise is mediated through nAChRs containing alpha7 or alpha9 subunits. Single cell imaging studies using FLUO-3 resolved two patterns of ACh-stimulated Ca2+ increase in the sperm head: 94% of responding sperm displayed a rise (59.6% +/- 5.7 SEM increase from resting fluorescence intensity), returning to resting levels over a period of 2-3 min. The remaining sperm (6%) displayed a sharp spike of Ca2+ ( approximately 1 min; 86% +/- 4.3 SEM change in fluorescence intensity), followed by abrupt loss of fluorescence, a pattern suggestive of AR. A Ca2+ influx in the sperm midpiece appeared to accompany the Ca2+ influx seen in the head. These observations confirm an ionotropic role for nAChRs in sperm function.

Quantification of digesta flow into the caeca.

1. A caecal intubation technique was developed to determine the amount of digesta that enters the caeca of fed and feed-deprived chickens. 2. Dry matter intakes per day for control and caecostomised chickens were not significantly different. 3. For fed and feed-deprived roosters, water intake was significantly increased by caecostomy in control birds and was significantly increased by feeding. 4. Amount of caecal dry matter excretion was significantly increased by feeding, but no difference in caecal water excretion was observed. 5. The ratio of caecal excretion (caecal/total excretion) of dry matter and water tended to decrease in response to feeding. 6. It is concluded that dry matter entry into the caeca represents 18% or 25% of the total dry matter excretion in fed or feed-deprived birds, respectively. Corresponding values for water entry are 17 and 26%. Therefore, the caeca play an important role in water balance.

Manganese induces endoplasmic reticulum (ER) stress and activates multiple caspases in nigral dopaminergic neuronal cells, SN4741.

Chronic exposure to manganese causes Parkinson's disease (PD)-like clinical symptoms (Neurotoxicology 5 (1984) 13; Arch. Neurol. 46 (1989) 1104; Neurology 56 (2001) 4). Occupational exposure to manganese is proposed as a risk factor in specific cases of idiopathic PD (Neurology 56 (2001) 8). We have investigated the mechanism of manganese neurotoxicity in nigral dopaminergic (DA) neurons using the DA cell line, SN4741 (J. Neurosci. 19 (1999) 10). Manganese treatment elicited endoplasmic reticulum (ER) stress responses, such as an increased level of the ER chaperone BiP, and simultaneously activated the ER resident caspase-12. Peak activation of other major initiator caspases-like activities, such as caspase-1, -8 and -9, ensued, resulting in activation of caspase-3-like activity during manganese-induced DA cell death. The neurotoxic cell death induced by manganese was significantly reduced in the Bcl-2-overexpressing DA cell lines. Our findings suggest that manganese-induced neurotoxicity is mediated in part by ER stress and considerably ameliorated by Bcl-2 overexpression in DA cells.

Phenotypic differentiation during migration of dopaminergic progenitor cells to the olfactory bulb.

A possible source for transplantable neurons in Parkinson's disease are adult olfactory bulb (OB) dopamine (DA) progenitors that originate in the anterior subventricular zone and reach the OB through the rostral migratory stream. We used adult transgenic mice expressing a lacZ reporter directed by an 8.9 kb tyrosine hydroxylase (TH) promoter to investigate the course of DAergic differentiation. Parallel transgene and intrinsic TH mRNA expression occurred during migration of DA interneurons through the mitral and superficial granule cell layers before these cells reached their final periglomerular position. Differential transgene and calcium-calmodulin-dependent protein kinase IV expression distinguished two nonoverlapping populations of interneurons. Transgenic mice carrying a TH8.9kb/lacZ construct with a mutant AP-1 site demonstrated that this element confers OB DA-specific TH gene regulation. These results indicate that DA phenotypic determination is specific to a subset of mobile OB progenitors.

Effects of caecal ligation and colostomy on water intake and excretion in chickens.

1. The effect of caecal ligation and colostomy on water intake and excretion were examined in chickens fed a low-protein diet or a low-protein diet supplemented with urea. 2. When fed a low-protein diet, the water intake and the ratio of water intake to food intake were increased by colostomy (P < 0.05) but not changed further by caecal ligation of colostomised chickens. 3. When fed a low-protein diet supplemented with urea, the amount of water intake and the ratio of water intake to food intake were not changed by either treatment. 4. Total water excretion was much higher in the colostomised plus caeca-ligated chickens than in other 3 groups fed both types of diet (P < 0.05). 5. The amount of faecal water excretion was increased by cecal ligation in colostomised chickens fed either diet (P < 0.01). 6. No effect of any treatment on water balance was observed in chickens fed either diet. 7. It is concluded that the lower intestine plays a useful role in the water economy of chickens fed a low-protein diet or a low-protein diet supplemented with urea.

Dopaminergic cell death induced by MPP(+), oxidant and specific neurotoxicants shares the common molecular mechanism.

Recent etiological study in twins (Tanner et al. 1999) strongly suggests that environmental factors play an important role in typical, non-familial Parkinson's disease (PD), beginning after age 50. Epidemiological risk factor analyses of typical PD cases have identified several neurotoxicants, including MPP(+) (the active metabolite of MPTP), paraquat, dieldrin, manganese and salsolinol. Here, we tested the hypothesis that these neurotoxic agents might induce cell death in our nigral dopaminergic cell line, SN4741 (Son et al. 1999) through a common molecular mechanism. Our initial experiments revealed that treatment with both MPP(+) and the other PD-related neurotoxicants induced apoptotic cell death in SN4741 cells, following initial increases of H(2)O(2)-related ROS activity and subsequent activation of JNK1/2 MAP kinases. Moreover, we have demonstrated that during dopaminergic cell death cascades, MPP(+), the neurotoxicants and an oxidant, H(2)O(2) equally induce the ROS-dependent events. Remarkably, the oxidant treatment alone induced similar sequential molecular events: ROS increase, activation of JNK MAP kinases, activation of the PITSLRE kinase, p110, by both Caspase-1 and Caspase-3-like activities and apoptotic cell death. Pharmacological intervention using the combination of the antioxidant Trolox and a pan-caspase inhibitor Boc-(Asp)-fmk (BAF) exerted significant neuroprotection against ROS-induced dopaminergic cell death. Finally, the high throughput cDNA microarray screening using the current model identified downstream response genes, such as heme oxygenase-1, a constituent of Lewy bodies, that can be the useful biomarkers to monitor the pathological conditions of dopaminergic neurons under neurotoxic insult.

The zona pellucida-initiated acrosome reaction: defect due to mutations in the sperm glycine receptor/Cl(-) channel.

The mammalian sperm acrosome reaction (AR) is essential to fertilization, and the egg zona pellucida (ZP) is generally believed to be an in vivo initiator of the fertilizing sperm AR. Previously a neuronal glycine receptor/Cl(-) channel (GlyR) was detected on the plasma membrane of mammalian sperm and earlier pharmacological studies suggested that this receptor/channel is important to the ZP-initiated AR. Here, sperm from mice with mutations in the neuronal GlyR alpha or beta subunits (spasmodic and spastic) were shown to be deficient in their ability to undergo the AR initiated in vitro by glycine or by solubilized ZP from mouse eggs. However, both spontaneous and calcium ionophore (A23187)-initiated AR were unaffected. The ZP-initiated AR in wild-type sperm was maximal after 2 h of capacitation, but capacitation of sperm from spasmodic mice for up to 3 h did not result in significant ZP-initiated AR. Similar results were observed when sperm from wild-type and spastic mice were compared. Testis from mice with the beta subunit mutation contained truncated beta subunit mRNAs. Moreover, a monoclonal antibody against GlyR completely blocked ZP initiation of AR in normal mouse sperm. Our results are consistent with an essential role for the sperm GlyR in the ZP-initiated AR.

Effect of removal of caecal contents on nitrogen utilisation and nitrogen excretion in caecally ligated chickens fed on a low protein diet supplemented with urea.

1. The effect of washing out the caecal contents on nitrogen utilisation and nitrogen excretion were examined in Single Comb White Leghorn cockerels fed on a 50 g/kg protein diet supplemented with urea. 2. Flushing out the caecal contents with saline in caecally ligated chickens produced a significantly increased nitrogen balance and increased nitrogen utilisation (P<0.05). 3. Washing out the caecal contents significantly decreased uric acid excretion but the treatment had no effect on urea and ammonia excretion. 4. Caecal bacterial contents were significantly decreased by caecal ligation and decreased further by washing out the caecal contents. 5. It is concluded that nitrogen metabolism in chickens is affected by possible changes in caecal fermentation produced by preventing substances from urine and digesta from entering the caeca.

Effect of caecectomy on growth, moisture in excreta, gastrointestinal passage time and uric acid excretion in growing chicks.

1. The effect of caecectomy on nitrogen utilisation and excretion was examined in growing chicks fed on a commercial diet. 2. Caecectomy had no significant effect on food intake or body weight gain. 3. Caecectomy caused significantly higher moisture content in excreta (P<0.01). 4. Gastrointestinal passage time of digesta was significantly shorter in caecectomised chicks than in control chicks (P<0.05). 5. Caecectomy tended to improve nitrogen utilisation rate in growing chicks. 6. The treatment significantly decreased uric acid excretion (P<0.01) and excretory uric acid-N/total nitrogen excretion (P<0.01). 7. It is concluded that the effects of caecectomy on nitrogen metabolism in growing chicks are similar to those in adult chickens.

Identification of potential compounds promoting BDNF production in nigral dopaminergic neurons: clinical implication in Parkinson's disease.

Parkinson's disease (PD) is characterized by the selective loss of dopamine (DA) neurons in the substantia nigral brain region. Currently, there is no cure or treatment that prevents such neuronal loss. Brain-derived neurotrophic factor (BDNF) has been found to support the survival of DA neurons in animal models and in primary cell cultures. However, the large molecular size of BDNF, coupled with the blood brain barrier, prevents its delivery to DA neurons to promote cell survival in the PD brain. The nigral DA neurons have the ability to produce BDNF for neuroprotection via either autocrine or paracrine mechanisms. Low mol. wt compounds were tested to see whether they could increase the production of BDNF in the DA neurons. The compounds tested include neurotransmitters, neuropeptides, intracellular signaling agents, known neuroprotective agents and growth factors. Our results demonstrate that salicyclic acid, cGMP analog, okadaic acid, IBMX, dipyridamole and glutamate significantly enhance BDNF production in DA neuronal cells.

The mouse sperm glycine receptor/chloride channel: cellular localization and involvement in the acrosome reaction initiated by glycine.

Previously, we reported that glycine initiates the in vitro acrosome reaction (AR) of porcine and human sperm by a mechanism that includes the glycine receptor/Cl- channel (GlyR) and that this receptor/channel is required for the zona-pellucida-initiated AR. Because mouse sperm are important tools in the study of fertilization, we investigated whether glycine initiated the mouse sperm AR and whether the sperm GlyR was involved in that initiation. Glycine (250 microM to 1 mM) initiated the AR of capacitated but not noncapacitated mouse sperm. The glycine-initiated AR was significantly inhibited by 50 nM strychnine, a neuronal GlyR antagonist. The neuronal GlyR agonists taurine and beta-alanine did not initiate the AR at 1 mM or 5 mM. A monoclonal antibody against the rat spinal cord GlyR significantly inhibited the glycine-initiated AR but not the spontaneous AR. Indirect immunofluorescence localization studies with that monoclonal antibody and postfixed live sperm detected 3 patterns of immunoreactivity involving 2 sites in the periacrosomal plasma membrane. These patterns were as follows: type A localization on the plasma membrane overlying the tip of the anterior acrosomal region; type B localization on the plasma membrane overlying the posterior part of the acrosomal equatorial segment and/or, in acrosome-reacted sperm, the posterior part of the modified equatorial segment; and type C localization that included both type A and type B. Type A and type C localization were only observed on the acrosome-intact sperm. During capacitation, the number of the sperm showing type A localization increased. Our results demonstrate that mouse sperm provide an excellent model for studying the role of the GlyR in the acrosome reaction.