The pathophysiology of visceral pain in patients with irritable bowel syndrome remains largely unknown. Our previous study showed that neonatal maternal deprivation (NMD) does not induce visceral hypersensitivity at the age of 6 weeks in rats. The aim of this study was to determine whether NMD followed by adult stress at the age of 6 weeks induces visceral pain in rats and to investigate the roles of adrenergic signaling in visceral pain. Here we showed that NMD rats exhibited visceral hypersensitivity 6 h and 24 h after the termination of adult multiple stressors (AMSs). The plasma level of norepinephrine was significantly increased in NMD rats after AMSs. Whole-cell patch-clamp recording showed that the excitability of dorsal root ganglion (DRG) neurons from NMD rats with AMSs was remarkably increased. The expression of β adrenergic receptors at the protein and mRNA levels was markedly higher in NMD rats with AMSs than in rats with NMD alone. Inhibition of β adrenergic receptors with propranolol or butoxamine enhanced the colorectal distention threshold and application of butoxamine also reversed the enhanced hypersensitivity of DRG neurons. Overall, our data demonstrate that AMS induces visceral hypersensitivity in NMD rats, in part due to enhanced NE-β adrenergic signaling in DRGs.
Adrenergic Agents ; pharmacology ; Animals ; Ganglia, Spinal ; drug effects ; Hyperalgesia ; drug therapy ; physiopathology ; Hypersensitivity ; drug therapy ; Male ; Maternal Deprivation ; Neurons ; drug effects ; Patch-Clamp Techniques ; methods ; Rats, Sprague-Dawley ; Signal Transduction ; drug effects ; Stress, Physiological ; physiology ; Visceral Pain ; chemically induced ; metabolism

PURPOSE: The aim of this study was to characterize the responsiveness of miniature excitatory postsynaptic currents (mEPSCs) to α1-adrenoceptor blockers in substantia gelatinosa (SG) neurons from the spinal cord to develop an explanation for the efficacy of α1-adrenoceptor blockers in micturition dysfunction. METHODS: Male adult Sprague-Dawley rats were used. Blind whole-cell patch-clamp recordings were performed using SG neurons in spinal cord slices. Naftopidil (100μM), tamsulosin (100μM), or silodosin (30μM), α1-adrenoceptor blockers, was perfused. The frequency of mEPSCs was recorded in an SG neuron to which the 3 blockers were applied sequentially with wash-out periods. Individual frequencies in a pair before naftopidil and tamsulosin perfusion were plotted as baseline, and the correlation between them was confirmed by Spearman correlation coefficient; linear regression was then performed. The same procedure was performed before naftopidil and silodosin perfusion. Frequencies of pairs after naftopidil and tamsulosin perfusion and after naftopidil and silodosin perfusion were similarly analyzed. The ratios of the frequencies after treatment to before were then calculated. RESULTS: After the treatments, Spearman ρ and the slope were decreased to 0.682 from 0.899 at baseline and 0.469 from 1.004 at baseline, respectively, in the tamsulosin group relative to the naftopidil group. In the silodosin group, Spearman ρ and the slope were also decreased to 0.659 from 0.889 at baseline and 0.305 from 0.989 at baseline, respectively, relative to the naftopidil group. Naftopidil significantly increased the ratio of the frequency of mEPSCs compared to tamsulosin and silodosin (P=0.015 and P=0.004, respectively). CONCLUSIONS: There was a difference in responsiveness in the frequency of mEPSCs to α1-adrenoceptor blockers, with the response to naftopidil being the greatest among the α1-adrenoceptor blockers. These data are helpful to understand the action mechanisms of α1-adrenoceptor blockers for male lower urinary tract symptoms in clinical usage.
Adrenergic alpha-1 Receptor Antagonists ; Adult ; Animals ; Excitatory Postsynaptic Potentials ; Humans ; Linear Models ; Lower Urinary Tract Symptoms ; Male ; Neurons ; Perfusion ; Rats ; Rats, Sprague-Dawley ; Spinal Cord ; Substantia Gelatinosa ; Urination

The autonomic nervous system plays critical roles in maintaining homeostasis in humans, directly regulating inflammation by altering the activity of the immune system. The cholinergic anti-inflammatory pathway is a well-studied neuroimmune interaction involving the vagus nerve. CD4-positive T cells expressing β2 adrenergic receptors and macrophages expressing the alpha 7 subunit of the nicotinic acetylcholine receptor in the spleen receive neurotransmitters such as norepinephrine and acetylcholine and are key mediators of the cholinergic anti-inflammatory pathway. Recent studies have demonstrated that vagus nerve stimulation, ultrasound, and restraint stress elicit protective effects against renal ischemia-reperfusion injury. These protective effects are induced primarily via activation of the cholinergic anti-inflammatory pathway. In addition to these immunological roles, nervous systems are directly related to homeostasis of renal physiology. Whole-kidney three-dimensional visualization using the tissue clearing technique CUBIC (clear, unobstructed brain/body imaging cocktails and computational analysis) has illustrated that renal sympathetic nerves are primarily distributed around arteries in the kidneys and denervated after ischemia-reperfusion injury. In contrast, artificial renal sympathetic denervation has a protective effect against kidney disease progression in murine models. Further studies are needed to elucidate how neural networks are involved in progression of kidney disease.
Acetylcholine ; Arteries ; Autonomic Nervous System ; Cholinergic Neurons ; Homeostasis ; Humans ; Immune System ; Inflammation ; Kidney Diseases ; Kidney ; Macrophages ; Nervous System ; Neurotransmitter Agents ; Norepinephrine ; Optogenetics ; Physiology ; Receptors, Adrenergic ; Receptors, Nicotinic ; Reperfusion Injury ; Spleen ; Sympathectomy ; Sympathetic Nervous System ; T-Lymphocytes ; Ultrasonography ; Vagus Nerve ; Vagus Nerve Stimulation

Previous studies have shown that electroacupuncture (EA) promotes recovery of motor function in Parkinson's disease (PD). However the mechanisms are not completely understood. Clinically, the subthalamic nucleus (STN) is a critical target for deep brain stimulation treatment of PD, and vesicular glutamate transporter 1 (VGluT1) plays an important role in the modulation of glutamate in the STN derived from the cortex. In this study, a 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD was treated with 100 Hz EA for 4 weeks. Immunohistochemical analysis of tyrosine hydroxylase (TH) showed that EA treatment had no effect on TH expression in the ipsilateral striatum or substantia nigra pars compacta, though it alleviated several of the parkinsonian motor symptoms. Compared with the hemi-parkinsonian rats without EA treatment, the 100 Hz EA treatment significantly decreased apomorphine-induced rotation and increased the latency in the Rotarod test. Notably, the EA treatment reversed the 6-OHDA-induced down-regulation of VGluT1 in the STN. The results demonstrated that EA alleviated motor symptoms and up-regulated VGluT1 in the ipsilateral STN of hemi-parkinsonian rats, suggesting that up-regulation of VGluT1 in the STN may be related to the effects of EA on parkinsonian motor symptoms via restoration of function in the cortico-STN pathway.
Adrenergic Agents ; toxicity ; Animals ; Apomorphine ; pharmacology ; Disease Models, Animal ; Dopamine Agonists ; pharmacology ; Electroacupuncture ; methods ; Functional Laterality ; drug effects ; Male ; Medial Forebrain Bundle ; injuries ; Motor Activity ; drug effects ; physiology ; Neurons ; drug effects ; metabolism ; Oxidopamine ; toxicity ; Parkinson Disease, Secondary ; chemically induced ; physiopathology ; therapy ; Rats ; Rats, Sprague-Dawley ; Subthalamic Nucleus ; drug effects ; metabolism ; pathology ; Tyrosine 3-Monooxygenase ; metabolism ; Up-Regulation ; drug effects ; physiology ; Vesicular Glutamate Transport Protein 1 ; metabolism

PURPOSE: The urinary bladder (UB) is innervated by both sensory and autonomic nerves. Recent studies have shown that sensory neuropeptides induced contractions in the detrusor muscle. Therefore, in a mouse model, we investigated the presence of interactions between the submucosal sensory nerves and the autonomic nerves that regulate the motor function of the detrusor muscle. METHODS: UB samples from male C57BL/6 mice were isolated, cut into strips, and mounted in an organ bath. Dose-response curves to norepinephrine and phenylephrine were studied in UB strips with and without mucosa, and the effects of preincubation with a receptor antagonist and various drugs on relaxation were also studied using tissue bath myography. RESULTS: Phenylephrine-induced relaxation of the UB strips showed concentration-related effects. This relaxation appeared in both mucosa-intact and mucosa-denuded UB strips, and was significantly inhibited by lidocaine, silodosin, and guanethidine (an adrenergic neuronal blocker). Meanwhile, phenylephrine-induced relaxation was inhibited by pretreatment with propranolol and calcitonin gene-related peptide (CGRP)–depletory capsaicin in UB strips with and without mucosa. CONCLUSIONS: The present study suggests that phenylephrine activates the α-1A adrenergic receptor (AR) of the sensory nerve, and then activates capsaicin-sensitive sensory nerves to release an unknown substance that facilitates the release of norepinephrine from adrenergic nerves. Subsequently, norepinephrine stimulates β-ARs in the detrusor muscle in mice, leading to neurogenic relaxation of the UB. Further animal and human studies are required to prove this concept and to validate its clinical usefulness.
Adrenergic Neurons ; Animals ; Autonomic Pathways ; Baths ; Calcitonin Gene-Related Peptide ; Capsaicin ; Guanethidine ; Humans ; Lidocaine ; Male ; Mice ; Mucous Membrane ; Myography ; Neuropeptides ; Norepinephrine ; Phenylephrine ; Propranolol ; Receptors, Adrenergic ; Receptors, Adrenergic, alpha-1 ; Relaxation ; Urinary Bladder*

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

OBJECTIVETo investigate the role of long non-coding RNA (lncRNA) BC088414 in hypoxic-ischemic injury of neural cells.

METHODSRat adrenal pheochromocytoma (PC12) cells were divided into four groups: normoxic, oxygen glucose deprivation (OGD), siRNA-normoxic (siRNA group) and siRNA-OGD (n=3 each). Cells were incubated in glucose-free and serum-free DMEM medium under the conditions of 37℃ and 1% O2+99% N2/CO2 for 6 hours to establish an in vitro hypoxic-ischemic model. Quantitative real-time PCR was used to measure mRNA expression of lncRNA BC088414, β2-adrenoceptor (Adrb2), and caspase-6 (CASP6). siRNAs were used to inhibit BC088414 expression in PC12 cells. The TUNEL method was used to measure cell apoptosis.

RESULTSThe OGD group had a significantly higher cell apoptotic index than the normoxic group (P<0.01). After inhibition of BC088414 expression, the OGD group had a significantly reduced apoptotic index (P<0.05). The OGD group had significantly higher mRNA expression levels of lncRNA BC088414, Adrb2, and CASP6 compared with the normoxic group (P<0.05). The siRNA -normoxic group had significantly lower mRNA expression levels of Adrb2 and CASP6 than the normoxic group (P<0.05), and the siRNA-OGD group also had significantly lower mRNA expression levels of Adrb2 and CASP6 than the OGD group (P<0.05).

CONCLUSIONSLncRNA BC088414 may promote apoptosis through Adrb2 and CASP6 and aggravate neural cell injury induced by hypoxia-ischemia.

Animals ; Apoptosis ; Caspase 6 ; genetics ; physiology ; Cell Hypoxia ; Neurons ; pathology ; PC12 Cells ; RNA, Long Noncoding ; physiology ; RNA, Messenger ; analysis ; Rats ; Receptors, Adrenergic, beta-2 ; genetics ; physiology

BACKGROUND/AIMS: Colonic peristalsis is mainly regulated via intrinsic neurons in guinea pigs. However, autonomic regulation of colonic motility is poorly understood. We explored a guinea pig model for the study of extrinsic nerve effects on the distal colon. METHODS: Guinea pigs were sacrificed, their distal colons isolated, preserving pelvic nerves (PN) and inferior mesenteric ganglia (IMG), and placed in a tissue bath. Fecal pellet propagation was conducted during PN and IMG stimulation at 10 Hz, 0.5 ms and 5 V. Distal colon was connected to a closed circuit system, and colonic motor responses were measured during PN and IMG stimulation. RESULTS: PN stimulation increased pellet velocity to 24.6 +/- 0.7 mm/sec (n = 20), while IMG stimulation decreased it to 2.0 +/- 0.2 mm/sec (n = 12), compared to controls (13.0 +/- 0.7 mm/sec, P < 0.01). In closed circuit experiments, PN stimulation increased the intraluminal pressure, which was abolished by atropine (10(-6) M) and hexamethonium (10(-4) M). PN stimulation reduced the incidence of non-coordinated contractions induced by NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) M). IMG stimulation attenuated intraluminal pressure increase, which was partially reversed by alpha-2 adrenoceptor antagonist (yohimbine; 10(-6) M). CONCLUSIONS: PN and IMG input determine speed of pellet progression and peristaltic reflex of the guinea pig distal colon. The stimulatory effects of PN involve nicotinic, muscarinic and nitrergic pathways. The inhibitory effects of IMG stimulation involve alpha-2 adrenoceptors.
Animals ; Atropine ; Autonomic Pathways* ; Baths ; Colon* ; Ganglia ; Guinea Pigs* ; Hexamethonium ; Incidence ; Neurons ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Peristalsis* ; Receptors, Adrenergic ; Reflex

Although the pelvic autonomic plexus may be considered a mixture of sympathetic and parasympathetic nerves, little information on its composite fibers is available. Using 10 donated elderly cadavers, we investigated in detail the topohistology of nerve fibers in the posterior part of the periprostatic region in males and the infero-anterior part of the paracolpium in females. Neuronal nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP) were used as parasympathetic nerve markers, and tyrosine hydroxylase (TH) was used as a marker of sympathetic nerves. In the region examined, nNOS-positive nerves (containing nNOS-positive fibers) were consistently predominant numerically. All fibers positive for these markers appeared to be thin, unmyelinated fibers. Accordingly, the pelvic plexus branches were classified into 5 types: triple-positive mixed nerves (nNOS+, VIP+, TH+, thick myelinated fibers + or -); double-positive mixed nerves (nNOS+, VIP-, TH+, thick myelinated fibers + or -); nerves in arterial walls (nNOS-, VIP+, TH+, thick myelinated fibers-); non-parasympathetic nerves (nNOS-, VIP-, TH+, thick myelinated fibers + or -); (although rare) pure sensory nerve candidates (nNOS-, VIP-, TH-, thick myelinated fibers+). Triple-positive nerves were 5-6 times more numerous in the paracolpium than in the periprostatic region. Usually, the parasympathetic nerve fibers did not occupy a specific site in a nerve, and were intermingled with sympathetic fibers. This morphology might be the result of an "incidentally" adopted nerve fiber route, rather than a target-specific pathway.
Adrenergic Fibers ; Aged* ; Cadaver* ; Female ; Humans ; Hypogastric Plexus* ; Male ; Myelin Sheath ; Nerve Fibers* ; Nitric Oxide Synthase Type I ; Tyrosine 3-Monooxygenase ; Vasoactive Intestinal Peptide

mRNAs of alpha-adrenoceptor (α-AR) subtypes are found in neurons in dorsal root ganglion (DRG) and change after peripheral nerve injury. In this study, the distribution of α-AR subtype proteins was studied in L5 DRG of normal rats and rats with chronic constriction injury of sciatic nerve (CCI). Using immunofluorescence technique, it was found that α1A-, α1B-, and α2A-AR proteins were expressed in large, medium, and small size neurons in normal DRG, and significantly increased in all size neurons 14 days after CCI. α1D- and α2C-AR was also expressed in all size neurons in normal DRG. However, α1D-AR was significantly increased and α2C-AR was decreased in small size neurons 14 days post CCI. α2B-AR neurons were not detectable in normal and CCI DRG. Co-expression of α1A- and α2A-AR in the same neuron was observed in normal DRG and increased post CCI. Collectively, these results indicated that there is distinct distribution of α-AR subtypes in DRG neurons, and the distribution and levels of expression of α-AR subtypes change differently after CCI. The up-regulation of α-AR subtypes in DRG neurons may play an important role in the process of generating and transmitting neuropathic pain.
Animals ; Cell Size ; Chronic Disease ; Constriction, Pathologic ; Fluorescent Antibody Technique ; Ganglia, Spinal ; metabolism ; pathology ; Male ; Microscopy, Confocal ; Neurons ; metabolism ; pathology ; Pain Measurement ; methods ; Pain Threshold ; Protein Isoforms ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenergic, alpha-1 ; metabolism ; Receptors, Adrenergic, alpha-2 ; metabolism ; Sciatic Nerve ; injuries ; surgery