Nerve Terminals Research Articles

The dorsal raphe-to-ventral hippocampal projection modulates reactive aggression through 5-HT1B receptors

Maladaptive reactive aggression is a core symptom of neuropsychiatric disorders such as schizophrenia. While uncontrolled aggression dampens societal safety, there is a limited understanding of the neural regulation involved in reactive aggression and its treatment. High levels of aggression have been linked to low serotonin (5-HT) levels. Additionally, post-weaning socially isolated (SI) mice exhibit outbursts of aggression following encountering acute stress, and hyperactivated ventral hippocampus (vHip) involves this stress-provoked escalated aggression. Here, we investigated the potential role of the raphe nucleus projecting to the vHip in modulating aggressive behavior. Chemogenetically activating the dorsal raphe nucleus (DRN) soma projecting the vHip or DRN nerve terminals in the vHip reduced reactive aggression. The reduction of attack behavior was abolished by the pretreatment of 5-HT1B receptor antagonist SB-224289. However, activating the median raphe nucleus (MRN)-to-vHip pathway ameliorated depression-like behavior but did not affect reactive aggression. DRN→vHip activation suppressed the vHip downstream area, the ventromedial hypothalamus (VMH), which is a core aggression area. Intra-vHip infusion of 5-HT1B receptor agonists (anpirtoline, CP-93129) suppressed reactive aggression and decreased c-Fos levels in the vHip neurons projecting to the VMH, suggesting an inhibition mechanism. Our findings indicate that activating the DRN projecting to the vHip is sufficient to inhibit reactive aggression in a 5-HT1B receptor-dependent manner. Thus, targeting 5-HT1B receptor could serve as a promising therapeutic approach to ameliorate symptoms of reactive aggression.

Albiflorin Decreases Glutamate Release from Rat Cerebral Cortex Nerve Terminals (Synaptosomes) through Depressing P/Q-Type Calcium Channels and Protein Kinase A Activity.

The purpose of this study was to investigate whether and how albiflorin, a natural monoterpene glycoside, affects the release of glutamate, one of the most important neurotransmitters involved in neurotoxicity, from cerebrocortical nerve terminals (synaptosomes) in rats. The results showed that albiflorin reduced 4-aminopyridine (4-AP)-elicited glutamate release from synaptosomes, which was abrogated in the absence of extracellular Ca2+ or in the presence of the vesicular glutamate transporter inhibitor or a P/Q-type Ca2+ channel inhibitor, indicating a mechanism of action involving Ca2+-dependent depression of vesicular exocytotic glutamate release. Albiflorin failed to alter the increase in the fluorescence intensity of 3,3-diethylthiacarbocyanine iodide (DiSC3(5)), a membrane-potential-sensitive dye. In addition, the suppression of protein kinase A (PKA) abolished the effect of albiflorin on glutamate release. Albiflorin also reduced the phosphorylation of PKA and synaptosomal-associated protein of 25 kDa (SNAP-25) and synapsin I at PKA-specific residues, which correlated with decreased available synaptic vesicles. The results of transmission electron microscopy (TEM) also observed that albiflorin reduces the release competence of synaptic vesicles evoked by 4-AP in synaptosomes. In conclusion, by studying synaptosomally released glutamate, we suggested that albiflorin reduces vesicular exocytotic glutamate release by decreasing extracellular Ca2+ entry via P/Q-type Ca2+ channels and reducing PKA-mediated synapsin I and SNAP-25 phosphorylation.

ANATOMICAL VARIATIONS IN A FINITE ELEMENT NERVE MODEL OF THE HUMAN FOOT

The nerves in the foot offer a significant role in controlling the movement and correct loading of the foot by providing continuous feedback to the central nervous system. The health importance in the anatomical variations of nerves, such as the locations, the lengths, the communicating branches, and the distance between the adjacent nerve terminals between individuals have given prominence to anatomists as well as physiologists. A previously developed one-dimensional (1D) model of the nerve was extended to determine different anatomical variations in the nerves of the foot, as a realistic anatomical-based variant nerve model of the human foot is not available. The model was verified against experimental data from the literature for communicating branches and distances of various area of the human foot. For instance, the simulated distances of the communicating branches of the plantar nerves and medial dorsal cutaneous nerve (MDCN) division proximal to the first digital space were found to be 43.3 mm and 112.3 mm, respectively, which was in general agreement with the experimental distances of 8-56 mm and 96-116.74 mm, respectively. The developed nerve variant model provides a platform for future studies of the various geometrical and efficient concerns of neurovascular diseases such as diabetic neuropathies by determining the parameters of nerve conduction studies.

Hybrid derivatives containing dimethyl fumarate and benzothiazole scaffolds for the potential treatment of multiple sclerosis; in silico & in vivo study.

Multiple Sclerosis (MS) is a chronic autoimmune, inflammatory neurological disease of the CNS. Riluzole and dimethyl fumarate (DMF) are two FDA-approved drugs to treat amyotrophic lateral sclerosis (ALS) and MS. Riluzole (a benzothiazole derivative) inhibits glutamate release from nerve terminals by antagonizing the N-Methyl-D-Aspartate (NMDA) receptor, and DMF upregulates anti-oxidative pathways. Herein, using molecular hybridization strategy, we synthesized some new hybrid structures of Riluzole and DMF through some common successive synthetic pathways for evaluating their potential activity for remyelination in MS treatment. Molecular docking experiments assessed the binding affinity of proposed structures to the NMDA active site. The designed structures were synthesized and purified based on well-known chemical synthesis procedures. Afterward, in vivoevaluation for their activity was done in the C57Bl/6 Cuprizone-induced demyelination MS model. The proposed derivatives were recognized to be potent enough based on docking studies (ΔGbind of all derivatives were -7.2 to -7.52 compare to the Ifenprodil (-6.98) and Riluzole (-4.42)). The correct structures of desired derivatives were confirmed using spectroscopic methods. Based onin vivostudies, D4 and D6 derivatives exhibited the best pharmacological results, although only D6 showed a statistically significant difference compared to the control. Also, for D4 and D6 derivatives, myelin staining confirmed reduced degeneration in the corpus callosum. Consequently,D4 and D6derivatives are promising candidates for developing new NMDA antagonists with therapeutic value against MS disorders.

Perioperative infusion of magnesium sulfate versus dexmedetomidine on the hemodynamic responses in patients undergoing laparoscopic cholecystectomy: A randomized controlled trial

Background: Laparoscopic cholecystectomy is associated with less post-operative pain, shorter hospitalization, and a faster functional recovery as compared to the open procedure. However, like any other surgery, a stress response is induced. Anesthesia interventions such as direct laryngoscopy, tracheal intubation, and extubation involve severe sympathetic stimulation. Magnesium can block the release of catecholamines from both the adrenal gland and adrenergic nerve terminals by inhibiting of activation of membrane Ca²⁺-ATPase and Na⁺-K⁺-ATPase. Aims and Objectives: Both magnesium sulfate and dexmedetomidine decrease the release of catecholamines and attenuate pressor responses to anesthesia and surgery. Materials and Methods: Eighty-four ASA I/II patients were randomly allocated to two groups. Group D received dexmedetomidine 1 μg/kg followed by 0.4 μg/kg/h and Group M received 2 g MgSO₄ followed by 15 mg/kg/h. hemodynamic variables were recorded as T0 (after loading dose of study drug), just before (T1) and 1, 2, and 3 min after ProSeal laryngeal mask airway (PLMA) insertion (T2 [i] [ii] [iii]), before and after peritoneal insufflation (T3 and T4), before and after table tilt (T5 and T6), after resuming flat position (T7), peritoneal deflation (T8), PLMA removal (T9), and on post-anesthesia care unit admission (T10). Data were collected and analyzed using SPSS 17 statistical software. Results: The demographic profile was comparable. After the study drug administration, there was a fall in mean arterial pressure (MAP) in both groups (Group D > Group M) and no pressor response to PLMA insertion. At peritoneal insufflation, the MAP increase was significantly more in Group M at T6, T7, and T8 (31.9%, 27.9%, and 35.6% above baseline, respectively). Although there was a fall in systolic blood pressure (SBP) from the baseline throughout the procedure in both groups, SBP was significantly higher at most times in Group M as compared to Group D (P<0.05). In both groups, there was a similar rise in diastolic blood pressure after peritoneal insufflation. The mean heart rate was significantly lower in Group D at all time points. Conclusion: Dexmedetomidine seemed to be superior to MgSO₄ for ameliorating hemodynamic responses in patients undergoing laparoscopic cholecystectomy.

Nerve entry points in the mimic musculature of the horse head.

Facial expressions are important in pain recognition in horses, but current observation-based pain scales remain subjective. A promising technique to quantitatively measure subtle changes in expression patterns, including changes invisible to the human eye, is surface electromyography (sEMG). To achieve high-quality and reliable sEMG signals, unilateral placement of bipolar electrodes is required in relation to the motor endplates (MEP). We aimed to localize the nerve entry points (NEPs; where the nerve branch first pierced the muscle belly) and the direction of the terminal nerve endings to estimate MEP locations of the innervating nerves in five equine facial muscles involved in pain expression. Three cadaveric Dutch Warmblood horse heads were dissected to identify the NEPs in the musculi caninus, levator anguli oculi medialis, nasolabialis, masseter and zygomaticus. These points were marked with pins and measured in relation to a reference line between two anatomical landmarks near the origin and insertion of the respective muscle. Relative distances were calculated from the most caudally situated landmark. NEPs were located at 33%-38% (caninus), 69%-86% (levator anguli oculi medialis) and 0%-18% (zygomaticus) from the caudal landmark. The nasolabialis showed two innervations zones. Its NEPs were located at 47%-72% (dorsal muscle branch) and 52%-91% (ventral branch). All terminal nerve endings were found to run in rostral direction. The masseter showed numerous NEPs diffusely spread within the muscle belly. Therefore, calculation of relative positions was not performed. These results could form the basis for feasibility studies and standardization of bipolar electrode positioning invivo to measure facial muscle activity patterns in horses.

Abstract Mo135: Correlation of Leptin Resistance With Attenuation of Cardiac Vagal Activation in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) is one of the most prominent diseases impacting individuals worldwide. A leading cause of death for T2DM patients is MI-related ventricular arrhythmia, which is associated with cardiac vagal nerve dysfunction. As T2DM patients exhibit leptin resistance, and leptin signaling has been implicated in heart rate regulation, we set out to characterize changes in cardiac vagal ganglionic neuron activity during development of T2DM and determine leptin signaling’s role in cardiac vagal dysfunction. In this study, T2DM was induced in Sprague-Dawley rats by feeding a high fat diet (HFD) plus a low dose streptozotocin injection. To characterize cardiac dysfunction, we measured arterial baroreflex sensitivity and found that 12 wks post-T2DM induction, rats experienced a diminished baroreflex response (gain max 0.62 ± 0.04 bpm/mm Hg T2DM vs. 2.21 ± 0.14 bpm/mm Hg sham). To determine if the change in baroreflex sensitivity is due to altered cardiac vagal nerve activity, we measured nAChR currents and cell excitability in intracardiac ganglion (ICG) neurons and found that T2DM rat cardiac vagal neurons exhibited reduced nAChR current density (213.9 ± 25.6 pA/pF T2DM vs. 375.5 ± 44.3 pA/pF sham) and action potential frequency (9.1 ± 0.5 spikes/s T2DM vs. 19.9 ± 1.4 spikes/s sham). Furthermore, acetylcholine release from cardiac vagal nerve terminals was attenuated in T2DM rats (0.4 ± 0.16 nM T2DM vs. 1.07 ± 0.12 nM sham). To determine the role of leptin signaling in the decrease of cardiac vagal nerve activity, we examined leptin and leptin receptor levels in ICG at 4, 8, and 12 wks post-T2DM induction. Western blots revealed elevated ICG leptin levels at 4, 8, and 12 wks post-T2DM induction (8.9 ± 0.7, 9.1 ± 1.3, and 11.7 ± 2.1 times sham level, respectively). qRT-PCR revealed reduced levels of leptin receptor transcript at 12 wks post-T2DM induction (48 ± 12% of sham). A reduction of leptin receptor protein in ICG neurons at 12 wks post-T2DM induction was observed using IF microscopy. These data demonstrate that T2DM reduces cardiac vagal nerve activity resulting in diminished control of cardiac functions such as the baroreflex. Furthermore, leptin resistance may play a role in this diminished cardiac function through reductions in leptin receptor levels.

Development of a 3-dimensional organotypic model with characteristics of peripheral sensory nerves

We developed a rat dorsal root ganglion (DRG)-derived sensory nerve organotypic model by culturing DRG explants on an organoid culture device. With this method, a large number of organotypic cultures can be produced simultaneously with high reproducibility simply by seeding DRG explants derived from rat embryos. Unlike previous DRG explant models, this organotypic model consists of a ganglion and an axon bundle with myelinated A fibers, unmyelinated C fibers, and stereo-myelin-forming nodes of Ranvier. The model also exhibits Ca2+ signaling in cell bodies in response to application of chemical stimuli to nerve terminals. Further, axonal transection increases the activating transcription factor 3 mRNA level in ganglia. Axons and myelin are shown to regenerate 14days following transection. Our sensory organotypic model enables analysis of neuronal excitability in response to pain stimuli and tracking of morphological changes in the axon bundle over weeks.

Adult-onset deletion of ATP13A2 in mice induces progressive nigrostriatal pathway dopaminergic degeneration and lysosomal abnormalities

Although most cases of Parkinson’s disease (PD) are sporadic, mutations in over 20 genes are known to cause heritable forms of the disease. Recessive loss-of-function mutations in ATP13A2, a lysosomal transmembrane P5B-type ATPase and polyamine exporter, can cause early-onset familial PD. Familial ATP13A2 mutations are also linked to related neurodegenerative diseases, including Kufor-Rakeb syndrome, hereditary spastic paraplegias, neuronal ceroid lipofuscinosis, and amyotrophic lateral sclerosis. Despite the severe effects of ATP13A2 mutations in humans, ATP13A2 knockout (KO) mice fail to exhibit neurodegeneration even at advanced ages, making it challenging to study the neuropathological effects of ATP13A2 loss in vivo. Germline deletion of ATP13A2 in rodents may trigger the upregulation of compensatory pathways during embryonic development that mask the full neurotoxic effects of ATP13A2 loss in the brain. To explore this idea, we selectively deleted ATP13A2 in the adult mouse brain by the unilateral delivery of an AAV-Cre vector into the substantia nigra of young adult mice carrying conditional loxP-flanked ATP13A2 KO alleles. We observe a progressive loss of striatal dopaminergic nerve terminals at 3 and 10 months after AAV-Cre delivery. Cre-injected mice also exhibit robust dopaminergic neuronal degeneration in the substantia nigra at 10 months. Adult-onset ATP13A2 KO also recreates many of the phenotypes observed in aged germline ATP13A2 KO mice, including lysosomal abnormalities, p62-positive inclusions, and neuroinflammation. Our study demonstrates that the adult-onset homozygous deletion of ATP13A2 in the nigrostriatal pathway produces robust and progressive dopaminergic neurodegeneration that serves as a useful in vivo model of ATP13A2-related neurodegenerative diseases.

Partners in health and disease: pineal gland and purinergic signalling.

In mammal's pineal glands, ATP interacts with the high-affinity P2Y1 and the low-affinity P2X7 receptors. ATP released from sympathetic nerve terminals potentiates noradrenaline-induced serotonin N-acetyltransferase (Snat) transcription, N-acetylserotonin (NAS), and melatonin (MLT) synthesis. Circulating melatonin impairs the expression of adhesion molecules in endothelial cells, blocking the migration of leukocytes. Acute defence response induced by pathogen- and danger/damage-associated molecular patterns (PAMPs and DAMPs) triggers the NF-κB pathway in pinealocytes and blocks the transcription of Snat. Therefore, the darkness hormone is not released, and neutrophils and monocytes migrate to the lesion sites. ATP released in high amounts from apoptotic and death cells was considered a DAMP, and the blockage of P2X7 receptors was tested as a new class of drugs for treating brain damage. However, this is not a simple equation. High ATP injected in a lateral ventricle blocked MLT, but not NAS, synthesis as it impairs the transcription of acetyl serotonin N-methyltransferase. NAS is released in the plasma and the cerebral spinal fluid. NAS also blocks the rolling and adhesion of leukocytes to endothelial cells. Otherwise, it is metabolised specifically in each brain area to provide the requested concentration of MLT as a neuroprotector. As observed in physiological conditions, high extracellular ATP, different from the other DAMPs, reports the environmental light/dark cycle rhythm because NAS substitutes MLT as the nocturnal chemical indicator, the darkness hormone. Thus, blocking the P2X7R should not be considered a universal therapy for improving acute strokes, as MLT and ATP are partners in health and disease.

Subthreshold activation of the melanocortin system causes generalized sensitization to anorectic agents in mice.

The melanocortin-3 receptor (MC3R) regulates GABA release from agouti-related protein (AgRP) nerve terminals and thus tonically suppresses multiple circuits involved in feeding behavior and energy homeostasis. Here, we examined the role of the MC3R and the melanocortin system in regulating the response to various anorexigenic agents. The genetic deletion or pharmacological inhibition of the MC3R, or subthreshold doses of an MC4R agonist, improved the dose responsiveness to glucagon-like peptide 1 (GLP1) agonists, as assayed by inhibition of food intake and weight loss. An enhanced anorectic response to the acute satiety factors peptide YY (PYY3-36) and cholecystokinin (CCK) and the long-term adipostatic factor leptin demonstrated that increased sensitivity to anorectic agents was a generalized result of MC3R antagonism. We observed enhanced neuronal activation in multiple hypothalamic nuclei using Fos IHC following low-dose liraglutide in MC3R-KO mice (Mc3r-/-), supporting the hypothesis that the MC3R is a negative regulator of circuits that control multiple aspects of feeding behavior. The enhanced anorectic response in Mc3r-/- mice after administration of GLP1 analogs was also independent of the incretin effects and malaise induced by GLP1 receptor (GLP1R) analogs, suggesting that MC3R antagonists or MC4R agonists may have value in enhancing the dose-response range of obesity therapeutics.

Morphophysiological aspects of the terminal nerve: literature review

Morphophysiological aspects of the terminal nerve: literature review

Delayed recruitment of activity-dependent bulk endocytosis in Fmr1 knockout neurons.

The presynapse performs an essential role in brain communication via the activity-dependent release of neurotransmitters. However, the sequence of events through which a presynapse acquires functionality is relatively poorly understood, which is surprising, since mutations in genes essential for its operation are heavily implicated in neurodevelopmental disorders. We addressed this gap in knowledge by determining the developmental trajectory of synaptic vesicle (SV) recycling pathways in primary cultures of rat hippocampal neurons. Exploiting a series of optical and morphological assays, we revealed that the majority of nerve terminals displayed activity-dependent calcium influx from 3 days invitro (DIV), immediately followed by functional evoked exocytosis and endocytosis, although the number of responsive nerve terminals continued to increase until the second week invitro. However, the most intriguing discovery was that activity-dependent bulk endocytosis (ADBE) was only observed from DIV 14 onwards. Importantly, optimal ADBE recruitment was delayed until DIV 21 in Fmr1 knockout neurons, which model Fragile X Syndrome (FXS). This implicates the delayed recruitment of ADBE as a potential contributing factor in the development of circuit dysfunction in FXS, and potentially other neurodevelopmental disorders.

Prognostic Value of Neurological Manifestations Related to COVID-19 Positive Patients: Observational Cross-Sectional Study

Abstract Background COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus. Corona virus affects the central nervous system in various different ways either through a retrograde transfer via the olfactory epithelium or through the cribriform bone and reaches the brain directly in seven days’ time or due to disruption of blood brain barrier which occurs during the viremia phase of illness and the virus will enter the brain directly. Another postulated mechanism is the invasion of peripheral nerve terminals by COVID-19 which then gains entry to the CNS through the synapse connected route. Objective To determine the prevalence of neurological symptoms and complications in COVID-19 patients and if we can use the neurological symptoms and its relevance as prognostic factors for disease severity. Patients and Methods This was a cross sectional study that was conducted on COVID-19 positive patients admitted to isolation ICU Ain Shams University Hospital through 4 months. Results The present study aimed to provide a comprehensive overview of neurologic manifestations associated with SARS-CoV-2 infection and to describe the clinical course and outcomes of COVID-19 patients with neurologic manifestations. Our results highlight the broad spectrum of neurological manifestations associated with SARS-CoV- 2 infection: the majority of neurologic manifestations were altered mental status (27.7%), anosmia (13.8%) followed by headache (12.5%). Conclusion the neurological manifestations are common in Covid-19 patients. There is an association between the presence of neurological manifestations and mortality.

Three-Dimensional Ultrastructure of Flower-Spray Nerve Endings in the Rat Carotid Sinus.

The flower-spray nerve endings are afferent nerve terminals in the carotid sinus that arise from carotid sinus nerve of glossopharyngeal nerve. However, the three-dimensional ultrastructural characteristics of flower-spray nerve endings and spatial relationships between the terminal parts and other cellular elements have not been fully understood. To elucidate their detailed relationship, backscattered electron imaging of serial sections was performed with a scanning electron microscope to produce a three-dimensional reconstruction of the flower-spray endings. The terminal parts of flower-spray endings were distributed horizontally approximately 5µm outside the external elastic membrane in the tunica adventitia of the internal carotid artery. The three-dimensional reconstruction showed that the terminal parts of flower-spray endings were flat with irregular contours and were partially covered by the thin cytoplasmic processes of Schwann cells. The complex consisting of the nerve terminals and associated Schwann cells was surrounded by a multilayered basement membrane. The terminal parts of the endings were also surrounded by fibroblasts with elastic fibers and collagen fibrils. Secretory vesicles without an electron-dense core were observed in the terminal parts of the endings. The accumulation of vesicles just below the axonal membrane was observed in terminal parts not covered by Schwann cell cytoplasmic processes on both the luminal and basal sides. Swollen mitochondria, concentric membranous structures, and glycogen granule-like electron-dense materials were often noted in some of the terminal parts of the endings and the parent axon. Collectively, the present results suggest that flower-spray endings are baroreceptors because their morphology was similar to other mechanoreceptors. Furthermore, flower-spray endings may be affected by glutamate secreted in an autocrine manner.

Harvesting, Embedding, and Culturing Dorsal Root Ganglia in Multi-compartment Devices to Study Peripheral Neuronal Features.

The most common peripheral neuronal feature of pain is a lowered stimulation threshold or hypersensitivity of terminal nerves from the dorsal root ganglia (DRG). One proposed cause of this hypersensitivity is associated with the interaction between immune cells in the peripheral tissue and neurons. In vitro models have provided foundational knowledge in understanding how these mechanisms result in nociceptor hypersensitivity. However, in vitro models face the challenge of translating efficacy to humans. To address this challenge, a physiologically and anatomically relevant in vitro model has been developed for the culture of intact dorsal root ganglia (DRGs) in three isolated compartments in a 48-well plate. Primary DRGs are harvested from adult Sprague Dawley rats after humane euthanasia. Excess nerve roots are trimmed, and the DRG is cut into appropriate sizes for culture. DRGs are then grown in natural hydrogels, enabling robust growth in all compartments. This multi-compartment system offers anatomically relevant isolation of the DRG cell bodies from neurites, physiologically relevant cell types, and mechanical properties to study the interactions between neural and immune cells. Thus, this culture platform provides a valuable tool for investigating treatment isolation strategies, ultimately leading to an improved screening approach for predicting pain.

Constitutive and Conditional Epitope Tagging of Endogenous G-Protein-Coupled Receptors in Drosophila.

To visualize the cellular and subcellular localization of neuromodulatory G-protein-coupled receptors in Drosophila, we implement a molecular strategy recently used to add epitope tags to ionotropic receptors at their endogenous loci. Leveraging evolutionary conservation to identify sites more likely to permit insertion of a tag, we generated constitutive and conditional tagged alleles for Drosophila 5-HT1A, 5-HT2A, 5-HT2B, Oct β 1R, Oct β 2R, two isoforms of OAMB, and mGluR The conditional alleles allow for the restricted expression of tagged receptor in specific cell types, an option not available for any previous reagents to label these proteins. We show expression patterns for these receptors in female brains and that 5-HT1A and 5-HT2B localize to the mushroom bodies (MBs) and central complex, respectively, as predicted by their roles in sleep. By contrast, the unexpected enrichment of Octβ1R in the central complex and of 5-HT1A and 5-HT2A to nerve terminals in lobular columnar cells in the visual system suggest new hypotheses about their functions at these sites. Using an additional tagged allele of the serotonin transporter, a marker of serotonergic tracts, we demonstrate diverse spatial relationships between postsynaptic 5-HT receptors and presynaptic 5-HT neurons, consistent with the importance of both synaptic and volume transmission. Finally, we use the conditional allele of 5-HT1A to show that it localizes to distinct sites within the MBs as both a postsynaptic receptor in Kenyon cells and a presynaptic autoreceptor.

Identification of adrenergic presynaptic and postsynaptic protein locations at neuromuscular junctions, their decrease during aging, and recovery by nicotinamide mononucleotide administration.

Neuromuscular junctions are innervated by motor and sympathetic nerves. The sympathetic modulation of motor innervation shows functional decline during aging, but the cellular and molecular mechanism of this change is not fully known. This study aimed to evaluate the effect of aging on sympathetic nerves and synaptic proteins at mouse neuromuscular junctions. Sympathetic nerves, presynaptic, and postsynaptic proteins of sympathetic nerves at neuromuscular junctions were visualized using immunohistochemistry, and aging-related changes were compared between adult-, aged-, and nicotinamide mononucleotide (NMN) administered aged mice. Sympathetic nerves were detected by anti-tyrosine hydroxylase antibody, and presynaptic protein vesicular monoamine transporter 2 colocalized with the sympathetic nerves. These two signals surrounded motor nerve terminals and acetylcholine receptor clusters. Postsynaptic neurotransmitter receptor β2-adrenergic receptors colocalized with motor nerve terminals and resided in reduced density at extrasynaptic sarcolemma. The signal intensity of the sympathetic nerve marker did not show a significant difference at neuromuscular junctions between 8.5-month-old adult mice and 25-month-old aged mice. However, the signal intensity of vesicular monoamine transporter 2 and β2-adrenergic receptors showed age-related decline at neuromuscular junctions. Interestingly, both age-related declines reverted to the adult level after 1 month of oral administration of NMN by drinking water. In contrast, NMN administration did not alter the expression level of sympathetic marker tyrosine hydroxylase at neuromuscular junctions. The results suggest a functional decline of sympathetic nerves at aged neuromuscular junctions due to decreases in presynaptic and postsynaptic proteins, which can be reverted to the adult level by NMN administration.

Aromatase inhibitors evoke periorbital allodynia in mice via calcitonin gene-related peptide and its receptors in Schwann cells

Background: Treatment with the currently recommended aromatase inhibitors (AIs) for adjuvant endocrine treatment of estrogen receptorpositive breast cancer is associated with debilitating musculoskeletal pain symptoms (AIMS) and headache. Recent evidence suggests that the proalgesic channel transient receptor potential ankyrin 1 (TRPA1) is implicated in AIMS. Here, we investigated the cellular and molecular mechanisms, including TRPA1, implicated in periorbital mechanical allodynia (PMA), a surrogate of headache-like pain, evoked by AIs in mice. Methods: C57BL6/J mice were treated with intragastric letrozole (0.05-0.5 mg/kg), exemestane (1-5 mg/kg) or anastrozole (0.02-0.2 mg/kg) and were evaluated by applying von Frey filaments to the periorbital region over the rostral portion of the eye. Some mice were pretreated (subcutaneous in the periorbital area) with receptor, channel, or enzyme inhibitors. PMA was also investigated in mice with selective silencing of Trpa1 and receptor activity modifying protein 1 [Ramp1, the component of calcitonin gene related peptide (CGRP) receptor required for its functioning] in Schwann cells (Plp-Cre+-Trpa1fl/fl and Plp-Cre+-Ramp1fl/fl mice, respectively) or trigeminal neurons (Adv-Cre+- Trpa1fl/fl and Adv- Cre+- Ramp1fl/fl mice, respectively). Results: Letrozole dose-dependently produced PMA that was attenuated by a TRPA1 antagonist (A967079) or a CGRP receptor antagonist (olcegepant), whereas indomethacin was ineffective. Selective silencing of Trpa1 in both Schwann cells and trigeminal neurons reduced letrozole- evoked PMA. Silencing of Ramp1 in Schwann cells, but not in trigeminal neurons, attenuated PMA. Inhibition of the intracellular pathway known to promote PMA by CGRP action in Schwann cells, including adenylyl cyclase (SQ-22536), nitric oxide synthase (L-NG-Nitro arginine methyl ester), and oxidative stress (N-tert-butyl-a-phenylnitrone) inhibitors reduced letrozole-evoked PMA. PMA evoked by exemestane (1, 5, 10 mg/kg i.g.) or anastrozole (0.02, 0.1, 0.2 mg/kg i.g.) Was also markedly reduced in mice with selective silencing of TRPA1 in Schwann cells and nociceptors. Conclusions: Data indicate that letrozole, targeting TRPA1 in peptidergic nerve terminals, releases CGRP that engages its receptor in adjacent Schwann cells to trigger a complex intracellular pathway that results in TRPA1 activation and the ensuing ROS release to sustain PMA. Should these mechanisms be present in patients, their inhibition may ameliorate cephalic mechanical allodynia associated with aromatase inhibitors-induced headaches.

Frankincense: A neuronutrient to approach Parkinson's disease treatment.

Parkinson's disease (PD), characterized by tremor, slowness of movement, stiffness, and poor balance, is due to a significant loss of dopaminergic neurons in the substantia nigra pars compacta and dopaminergic nerve terminals in the striatum with deficit of dopamine. To date the mechanisms sustaining PD pathogenesis are under investigation; however, a solid body of experimental evidence involves neuroinflammation, mitochondrial dysfunction, oxidative stress, and apoptotic cell death as the crucial factors operating in the pathogenesis of PD. Nutrition is known to modulate neuroinflammatory processes implicated in the pathogenesis and progression of this neurodegenerative disorder. Consistent with this notion, the Burseraceae family, which includes the genera Boswellia and Commiphora, are attracting emerging interest in the treatment of a wide range of pathological conditions, including neuroinflammation and cognitive decline. Bioactive components present in these species have been shown to improve cognitive function and to protect neurons from degeneration in in vitro, animal, as well as clinical research. These effects are mediated through the anti-inflammatory, antiamyloidogenic, anti-apoptotic, and antioxidative properties of bioactive components. Although many studies have exploited possible therapeutic approaches, data from human studies are lacking and their neuroprotective potential makes them a promising option for preventing and treating major neurodegenerative disorders.