Our research reveals the critical role of the suprachiasmatic nucleus (SCN) vasoactive intestinal peptide (VIP) neurons in mediating light-induced transient forgetting. Acute exposure to bright light selectively impairs trace fear memory by activating VIP neurons in the SCN, as demonstrated by increased c-Fos expression and Ca²⁺ recording. This effect can be replicated and reversed through optogenetic and chemogenetic manipulations of SCN VIP neurons. Furthermore, we identify the SCN → PVT (paraventricular nucleus of the thalamus) VIP neuronal circuitry as essential in this process. These findings establish a novel role for SCN VIP neurons in modulating memory accessibility in response to environmental light cues, extending their known function beyond circadian regulation and revealing a mechanism for transient forgetting.
Animals ; Vasoactive Intestinal Peptide/metabolism* ; Male ; Mice ; Neurons/metabolism* ; Suprachiasmatic Nucleus/physiology* ; Light ; Mice, Inbred C57BL ; Memory/physiology* ; Fear/physiology* ; Suprachiasmatic Nucleus Neurons/metabolism* ; Optogenetics ; Proto-Oncogene Proteins c-fos/metabolism*

The anterior cingulate cortex (ACC) has recently been proposed as a key player in the representation of itch stimuli. However, to date, little is known about the contribution of specific ACC interneuron populations to itch processing. Using c-Fos immunolabeling and in vivo Ca²⁺ imaging, we reported that both histamine and chloroquine stimuli-induced acute itch caused a marked enhancement of vasoactive intestinal peptide (VIP)-expressing interneuron activity in the ACC. Behavioral data indicated that optogenetic and chemogenetic activation of these neurons reduced scratching responses related to histaminergic and non-histaminergic acute itch. Similar neural activity and modulatory role of these neurons were seen in mice with chronic itch induced by contact dermatitis. Together, this study highlights the importance of ACC VIP⁺ neurons in modulating itch-related affect and behavior, which may help us to develop novel mechanism-based strategies to treat refractory chronic itch in the clinic.
Animals ; Pruritus/physiopathology* ; Vasoactive Intestinal Peptide/metabolism* ; Interneurons/metabolism* ; Gyrus Cinguli/metabolism* ; Mice ; Male ; Mice, Inbred C57BL ; Histamine ; Chloroquine ; Optogenetics ; Mice, Transgenic

OBJECTIVES: To observe the effects of electroacupuncture (EA) at "Neiguan" (PC 6) and "Zusanli"(ST 36) on the gastric emptying rate, the level of serotonin (5-HT) and the protein expression of motilin (MTL), ghrelin, substance P (SP) and vasoactive intestinal peptide (VIP) in the antral tissue of the rats with functional dyspepsia (FD) and explore the effect mechanism of EA in treatment of FD. METHODS: A total of 21 SPF male SD rat pups were randomly divided into a normal group, a model group and an EA group, with 7 rats in each group. In the model group and the EA group, FD model was prepared by the gavage with 0.1% sucrose iodoacetamide solution combined with the modified small platform method. After the successful modeling, EA was applied to "Neiguan" (PC 6) and "Zusanli"(ST 36) in the rats of the EA group, with disperse-dense wave, 20 Hz/100 Hz in frequency, stimulated for 30 min, once daily, for 7 days consecutively. Before and after intervention, the general condition of the rats was observed in each group. After the completion of intervention, the gastric emptying rate was measured, the morphological changes of gastric antral tissue were observed using HE staining, the level of 5-HT was detected with ELISA method, and the protein expression of MTL, ghrelin, SP, and VIP was determined with Western blot method in the antral tissue of rats. RESULTS: In the normal group, the rats were in a good mental state, with lustrous fur, flexible movement and the increase of food intake and body mass. In the model group, the rats were poor in mental state, lack of lustre in fur, preference for the body curled up, reduced activity and response; and a part of rats had loose stool, obviously enlarged gastric body and gastric food retention. In the EA group, the general condition of rats, e.g. the mental state, food intake and activity, were improved, the gastric body got smaller obviously and the gastric food retention was reduced when compared with the model group. The antral structure was intact, the glands were rich and no injury of the gastric mucosa was found, e.g. inflammatory reaction and edema in the rats of each group. Compared with the normal group, the gastric emptying rate was decreased (P<0.01), 5-HT level was increased (P<0.01), the protein expression of MTL and ghrelin was reduced (P<0.01) and that of VIP was elevated (P<0.01) in the rats of the model group. The gastric emptying rate was increased (P<0.01), 5-HT level was decreased (P<0.01), and the protein expression of MTL and ghrelin was elevated (P<0.05, P<0.01) in the rats of the EA group when compared with those in the model group. CONCLUSIONS Electroacupuncture at "Neiguan" (PC 6) and "Zusanli"(ST 36) may effectively relieve gastric dysfunction, strengthen gastric motility and promote gastric emptying so as to alleviate the symptoms of dyspepsia in FD rats, and its mechanism may be related to the regulation of gastrointestinal hormones in the antral tissue.
Rats ; Male ; Animals ; Electroacupuncture ; Dyspepsia/therapy* ; Rats, Sprague-Dawley ; Ghrelin ; Gastrointestinal Hormones ; Serotonin ; Vasoactive Intestinal Peptide ; Acupuncture Points

Viral infection is clinically common and some viral diseases, such as the ongoing global outbreak of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), have high morbidity and mortality. However, most viral infections are currently lacking in specific therapeutic agents and effective prophylactic vaccines, due to inadequate response, increased rate of drug resistance and severe adverse side effects. Therefore, it is urgent to find new specific therapeutic targets for antiviral defense among which "peptide-based therapeutics" is an emerging field. Peptides may be promising antiviral drugs because of their high efficacy and low toxic side effects. Vasoactive intestinal peptide (VIP) is a prospective antiviral peptide. Since its successful isolation in 1970, VIP has been reported to be involved in infections of SARS-CoV-2, human immune deficiency virus (HIV), vesicular stomatitis virus (VSV), respiratory syncytial virus (RSV), Zika virus (ZIKV) and cytomegalovirus (CMV). Additionally, given that viral attacks sometimes cause severe complications due to overaction of inflammatory and immune responses, the potent anti-inflammatory and immunoregulator properties of VIP facilitate it to be a powerful and promising candidate. This review summarizes the role and mechanisms of VIP in all reported viral infections and suggests its clinical potential as an antiviral therapeutic target.
Antiviral Agents/therapeutic use* ; COVID-19/drug therapy* ; Humans ; Prospective Studies ; SARS-CoV-2 ; Vasoactive Intestinal Peptide/therapeutic use* ; Zika Virus ; Zika Virus Infection/drug therapy*

OBJECTIVE: To investigate the protective effect of Zengye Decoction (, ZYD) on the submandibular glands (SMGs) in nonobese diabetic (NOD) mice. METHODS: Twenty-seven female NOD mice were randomly equally divided into 3 groups: the model group, the hydroxychloroquine (HCQ) group, and the ZYD group. Nine C57/B6 mice served as the normal group. After 1-week acclimation, the HCQ and ZYD groups were intragastrically administered with HCQ and ZYD, respectively, and the normal and model groups were administered with normal saline. Changes in the salivary flow rate were observed. Mice from all 4 groups were sacrificed at the age of 20 weeks. The serum and SMGs were collected. Serum cytokines gamma-interferon (IFN-γ), interleukin-10 (IL-10) were detected by enzyme-linked immunosorbent assay. Histological changes in the submandibular glands were examined by hematoxylin and eosin staining. The mRNA expression of IFN-γ, IL-10 and vasoactive intestinal peptide (VIP) in the submandibular glands were measured by real-time polymerase chain reaction. RESULTS: Compared with the model group, the salivary flow of the ZYD group significantly increased (P<0.05), the extent of the histological changes was ameliorated (P<0.05), and the Th1/Th2 cytokine imbalance was remedied (P<0.05). In the ZYD-treated mice, the VIP mRNA was up-regulated (P<0.05). CONCLUSIONS ZYD is beneficial in protecting structure and function of SMGs in NOD mice. The mechanism may be associated with the correction of the Th1/Th2 cytokine imbalance, and with the prevention of a progressive decline of the VIP level.
Animals ; Cytokines ; blood ; Drugs, Chinese Herbal ; pharmacology ; Female ; Mice ; Mice, Inbred C57BL ; Mice, Inbred NOD ; Salivation ; drug effects ; Sjogren's Syndrome ; drug therapy ; immunology ; Submandibular Gland ; drug effects ; pathology ; Th1 Cells ; immunology ; Th2 Cells ; immunology ; Vasoactive Intestinal Peptide ; genetics

Background: Previous studies demonstrate that eccrine sweat glands are innervated by both cholinergic and adrenergic nerves. However, it is still unknown whether the secretory coils and ducts of eccrine sweat glands are equally innervated by the sympathetic nerve fibers. To well understand the mechanisms on sweat secretion and reabsorption, the differential innervation of secretory coils and ducts in human eccrine sweat glands was investigated in the study. Methods: From June 2016 to June 2017, six human skins were fixed, paraffin-embedded, and cut into 5 μm-thick sections, followed by costaining for nerve fiber markers protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH) and vasoactive intestinal peptide (VIP), and eccrine sweat gland markers K7, S100P, and K14 by combining standard immunofluorescence with tyramide signal amplification (IF-TSA). Stained sections were observed under the microscope, photographed, and analyzed. Results: The fluorescent signals of PGP 9.5, TH, and VIP were easily visualized, by IF-TSA, as circular patterns surrounding eccrine sweat glands, but only PGP 9.5 could be observed by standard IF. The IF-TSA method is more sensitivity than standard IF in detecting antigens expressed at low levels. PGP 9.5, TH, and VIP appeared primarily surrounding the secretory coils and sparsely surrounding the sweat ducts. Conclusion Sweat secretion is mainly controlled by autonomic nerves whereas sweat reabsorption is less affected by nerve activity.
Eccrine Glands ; innervation ; Fluorescent Antibody Technique ; Humans ; Nerve Fibers ; Sweat Glands ; innervation ; Vasoactive Intestinal Peptide ; analysis

OBJECTIVETo investigate the effects of vasoactive intestinal peptide (VIP) on the airway inflammation and its regulatory effect on Th17/Treg imbalance in asthmatic mice.

METHODSA total of 30 BALB/c mice were equally and randomly divided into three groups: control, asthma, and VIP. An acute asthmatic mouse model was established by sensitization and challenge with ovalbumin (OVA). The control group received normal saline instead of OVA. Before the challenge with OVA, the VIP group was administered VIP (20 μg/mL) by aerosol inhalation for 30 minutes. The bronchoalveolar lavage fluid (BALF) and the lung tissue were collected from mice. The pathological changes in the lung tissue were observed by hematoxylin and eosin staining. The levels of Th17/Treg-related cytokines in BALF were measured by enzyme-linked immunosorbent assay. The expression of retinoid-related orphan receptor gamma t (RORγt) and forkhead box P3 (Foxp3) were measured by real-time fluorescence quantitative PCR and immunohistochemistry.

RESULTSThe histopathological results showed that the VIP group had milder symptoms of airway inflammation than the asthma group. The level of IL-17 in BALF in the asthma group was significantly higher than that in the control group and the VIP group (P<0.01), but the level of IL-17 in the control group was significantly lower than that in the VIP group (P<0.01). The level of IL-10 in BALF in the asthma group was significantly lower than that in the control group and the VIP group (P<0.01, but the level of IL-10 in the VIP group was significantly higher than that in the control group (P<0.01). The asthma group showed significantly higher expression levels of RORγt mRNA and protein in the lung tissue and significantly lower expression levels of Foxp3 mRNA and protein than the control group (P<0.01). The VIP group had significantly lower expression levels of RORγt mRNA and protein in the lung tissue and significantly higher expression levels of Foxp3 mRNA and protein than the asthma group (P<0.05).

CONCLUSIONSThe Th17/Treg imbalance may be closely related to the airway inflammation in asthmatic mice. VIP can improve airway inflammation by regulating the Th17/Treg imbalance in asthmatic mice.

Animals ; Asthma ; drug therapy ; immunology ; Forkhead Transcription Factors ; genetics ; Interleukin-10 ; analysis ; Interleukin-17 ; analysis ; Male ; Mice ; Mice, Inbred BALB C ; Nuclear Receptor Subfamily 1, Group F, Member 3 ; genetics ; T-Lymphocytes, Regulatory ; immunology ; Th17 Cells ; immunology ; Vasoactive Intestinal Peptide ; pharmacology ; therapeutic use

The frontal nerve is characterized by its great content of sympathetic nerve fibers in contrast to cutaneous branches of the maxillary and mandibular nerves. However, we needed to add information about composite fibers of cutaneous branches of the nasociliary nerve. Using cadaveric specimens from 20 donated cadavers (mean age, 85), we performed immunohistochemistry of tyrosine hydroxylase (TH), neuronal nitric oxide synthase (nNOS), and vasoactive intestinal polypeptide (VIP). The nasocilliary nerve contained abundant nNOS-positive fibers in contrast to few TH- and VIP-positive fibers. The short ciliary nerves also contained nNOS-positive fibers, but TH-positive fibers were more numerous than nNOS-positive ones. Parasympathetic innervation to the sweat gland is well known, but the original nerve course seemed not to be demonstrated yet. The present study may be the first report on a skin nerve containing abundant nNOS-positive fibers. The unique parasympathetic contents in the nasocilliary nerve seemed to supply the forehead sweat glands as well as glands in the eyelid and nasal epithelium.
Cadaver ; Eyelids ; Forehead ; Humans* ; Immunohistochemistry ; Mandibular Nerve ; Nasal Mucosa ; Nerve Fibers ; Nitric Oxide Synthase Type I ; Skin ; Sweat Glands ; Tyrosine 3-Monooxygenase ; Vasoactive Intestinal Peptide

OBJECTIVETo study the effects of sacral nerve root electrostimulation (SNS) on the colon function and its mechanisms in rats with spinal cord injury (SCI).

METHODSOne hundred and four Wistar rats were divided into three groups: A, B and C. A group ( n = 24) was divided into three subgroups (n = 8) for studying the bioelectricity: Normal group (NG), SCI group (SCI) and SCI group with SNS(SNS); B group( n = 24) was divided into three subgroups( n = 8) for studying the colon motility: NG, SCI and SNS. C group( n = 56) were divided into three groups for studying the change of morphology and neurotransmitters(SP and VIP): NG (n = 8), SCI (n = 24), and SNS (n = 24) . In SCI and SNS, included of three subgroups: 24, 48, 72 h after spinal cord injury (n = 8).

RESULTSIn SCI group, the activity of bioelectricity in proximal and distal colon was reduced; the colon motility was lessened, and colon mucosa appeared different degree of damage; cell-cell connections between intestinal epithelial cells were destroyed. The expressions of substance P(SP) and vasoactive intestinal peptide (VIP) in colon were decreased obviously. SNS was found to activate the bioelectricity, promote the colon motility, improve the intestinal mucosal, and increase the expressions of SP and VIP. Conclusion: SNS can activate the peristalsis, rehabilitate the motility of denervated colon, protection of the intestinal mechanical barrier between intestinal epithelial cells and tight junction, rebuild the colon function through activating the bioelectricity and increase the expressions of SP and VIP.

Animals ; Colon ; physiopathology ; Electric Stimulation Therapy ; Epithelial Cells ; drug effects ; Intestinal Mucosa ; drug effects ; Lumbosacral Region ; innervation ; Neurotransmitter Agents ; metabolism ; Rats ; Rats, Wistar ; Spinal Cord Injuries ; therapy ; Substance P ; metabolism ; Vasoactive Intestinal Peptide ; metabolism

BACKGROUND/AIMS: The internal anal sphincter (IAS) plays an important role in maintaining continence and a number of neurotransmitters are known to regulate IAS tone. The aim of this study was to determine the relative importance of the neurotransmitters involved in the relaxant and contractile responses of the porcine IAS. METHODS: Responses of isolated strips of IAS to electrical field stimulation (EFS) were obtained in the absence and presence of inhibitors of neurotransmitter systems. RESULTS: Contractile responses of the sphincter to EFS were unaffected by the muscarinic receptor antagonist, atropine (1 muM), but were almost completely abolished by the adrenergic neuron blocker guanethidine (10 muM). Contractile responses were also reduced (by 45% at 5 Hz, P < 0.01) following desensitisation of purinergic receptors with alpha,beta-methylene-ATP (10 muM). In the presence of guanethidine, atropine, and alpha,beta-methylene-ATP, the remaining relaxatory responses to EFS were examined. These responses were not altered by the cyclooxygenase inhibitor, indomethacin (5 muM), the vasoactive intestinal polypeptide receptor antagonist, [D-p-Cl-Phe6,Leu17]-vasoactive intestinal peptide (PheLeu-VIP; 100 nM), or the purinoceptor antagonists, 8-phenyltheophyline (P1 receptors) or suramin (P2 receptors). However, relaxation responses were reduced by Nomega-nitro-L-arginine (L-NNA; 100 muM), an inhibitor of nitric oxide synthesis (40-50% reduction), zinc protoprophyrin IX (10 muM), an inhibitor of carbon monoxide synthesis (20-40% reduction), and also propargylglycine (30 muM) and aminooxyacetic acid (30 muM), inhibitors of hydrogen sulphide synthesis (15-20% reduction). CONCLUSIONS: Stimulation of IAS efferent nerves releases excitatory and inhibitory neurotransmitters: noradrenaline is the predominant contractile transmitter with a smaller component from ATP, whilst 3 gases mediate relaxation responses to EFS, with the combined contributions being nitric oxide > carbon monoxide > hydrogen sulfide.
Adenosine Triphosphate ; Adrenergic Neurons ; Aminooxyacetic Acid ; Anal Canal* ; Atropine ; Autonomic Pathways ; Carbon Monoxide* ; Carbon* ; Gases ; Guanethidine ; Hydrogen Sulfide* ; Hydrogen* ; Indomethacin ; Neurotransmitter Agents* ; Nitric Oxide* ; Norepinephrine ; Prostaglandin-Endoperoxide Synthases ; Purinergic Antagonists ; Receptors, Muscarinic ; Receptors, Purinergic ; Relaxation* ; Suramin ; Vasoactive Intestinal Peptide ; Zinc