Migraine and anxiety disorders are frequently co-morbid with balance disorders. Potential mechanisms for migrainous vertigo include sites of action of 5-HT (serotonin) 1B and 1D receptor agonists such as rizatriptan, which attenuate motion sickness in migraineurs. Selective serotonin reuptake inhibitors (SSRIs) are also known to be efficacious in the treatment of vertigo. Relative distribution of the 5-HT receptor subtypes and their functional roles in the vestibular nuclei and inner ear is still unknown. Using 5-HT1A, 1B, AND 1D receptors-specific antibody, we have demonstrated a differential distribution of these receptor subtypes within the rat vestibular nuclei and inner ear. For 5-HT receptor subtypes expression in the vestibular and auditory periphery, most ganglion cells in the vestibular ganglion showed immunoreactivity for 5-HT1A, 5-HT1B and 5-HT1D receptors. In addition, 5-HT1B and 1D receptors immunopositive reactivities were associated with endothelial cells of small blood vessels in the vestibular ganglion and nerve, endothelial cells in both the spiral ligament deep to the spiral prominence and stria vascularis and endothelial cells on blood vessels along the margins of the spiral ganglion. For 5-HT receptor subtypes expression in the vestibular nuclei (VN), the 5-HT1A, 1B and 1D receptors were expressed differentially in the VN. Fine varicose axons in the periventricular plexus showed intense 5-HT1A receptor expression in the medial VN (MVN) and extended into the superior VN (SVN). By contrast, 5-HT1B receptors were not expressed the ventricular plexus axons. Rather, 5-HT1B and 1D receptors immunopositive cell bodies and neuronal processes were dense in rostral MVN, dorsal SVN, lateral VN (LVN) and ventral aspect of nucleus prepositus hypoglossi (NPH). In the present study, inner ear and vestibular nuclei showed distinct distributions of 5- HT1A, 1B and 1D receptors expressions that are parallel to their distribution in peripheral and central nociceptive pathways. These differentially distributed 5-HT receptor subtypes are potential targets to explain the efficacy of SSRIs and triptans in treating migraine and migrainous vertigo.
Animals ; Anxiety Disorders ; Axons ; Blood Vessels ; Ear, Inner ; Endothelial Cells ; Ganglion Cysts ; Migraine Disorders ; Motion Sickness ; Neurons ; Rats ; Receptor, Serotonin, 5-HT1A ; Receptor, Serotonin, 5-HT1B ; Receptor, Serotonin, 5-HT1D ; Serotonin ; Serotonin Uptake Inhibitors ; Spiral Ganglion ; Spiral Ligament of Cochlea ; Stria Vascularis ; Triazoles ; Tryptamines ; Vertigo ; Vestibular Nuclei

OBJECTIVETo assess whether HTR1A and HTR1B polymorphisms are associated with the predisposition, gender, PUMC Classification and/or severity of adolescent idiopathic scoliosis (AIS).

METHODSRs6294 (HTR1A) and rs6296 (HTR1B) were genotyped in 103 AIS patients treated from January 2006 to March 2007, and 108 controls with matched gender and age. The data were analyzed by the allelic and genotypic association analysis, and the genotype-phenotype (gender, PUMC Classification, and Cobb angle) association analysis.

RESULTSThe distributions of the alleles of all the 2 SNPs met Hardy-Weinberg equilibrium in the controls (goodness-of-fit chi(2) test, P > 0.05). The allele A of rs6294 was related with the occurrence of AIS (P = 0.041), but differences of the allele frequencies of rs6296 and the genotype frequencies of both SNPs between 2 groups had no statistical significance (P > 0.05). The genotype A/A + A/G of rs6294 was associated with AIS PUMC type III, and there was no other positive results in genotype-phenotype association analysis.

CONCLUSIONThese results suggest that HTR1A may be a predisposition gene of AIS PUMC type III, and PUMC Classification may has its genetic basis.

Adolescent ; Gene Frequency ; Genetic Association Studies ; Genotype ; Humans ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptor, Serotonin, 5-HT1A ; genetics ; Receptor, Serotonin, 5-HT1B ; genetics ; Scoliosis ; genetics

A number of studies have demonstrated that 5-hydroxytryptamine (5-HT) can induce muscle contraction or relaxation response and enhance secretion in the gastrointestinal tract via a multiplicity of 5-HT receptor subtypes. In the present study, we investigated the pharmacological characterization of the 5-HT-induced contractile response in longitudinal smooth muscle isolated from the feline ileum. Addition of 5-HT into muscle chambers enhanced the basal tone and spontaneous activity in a concentration-dependent manner. The neurotoxin tetrodotoxin did not alter the 5-HT-induced contraction of the longitudinal muscles. Neither atropine nor guanethidine affected the contraction. The 5-HT agonists, 5-methylserotonin hydrochloride and mosapride, also evoked concentration-dependent contractions. The 5-HT-induced contraction was enhanced by the 5HT2 receptor antagonist ketanserin and the 5-HT3 receptor antagonist ondansetron but was inhibited by the 5-HT1 receptor antagonist methysergide and 5-HT4 receptor antagonist GR113808. These results indicate that 5-HT1 and 5-HT4 receptors may mediate the contraction of the 5-HT-induced response and 5-HT2 and 5-HT3 receptors may mediate 5-HT-induced relaxation in feline ileal longitudinal smooth muscles.
Atropine ; Benzamides ; Contracts ; Gastrointestinal Tract ; Guanethidine ; Ileum ; Indoles ; Ketanserin ; Methysergide ; Morpholines ; Muscle Contraction ; Muscle, Smooth ; Muscles ; Ondansetron ; Receptors, Serotonin ; Receptors, Serotonin, 5-HT1 ; Receptors, Serotonin, 5-HT3 ; Receptors, Serotonin, 5-HT4 ; Relaxation ; Serotonin ; Serotonin Receptor Agonists ; Sulfonamides ; Tetrodotoxin

It has been known that central tryptaminergic system is closely related with the regulation of renal function, and that central 5-HT1 receptors mediate diuresis and natriuresis, whereas central 5-HT2 and 5-HT3 receptors mediate antidiuresis and antinatriuresis. Among many subtypes of 5-HT1 receptors, central 5-HT1A subtype has been suggested to exert diuretic and natriuretic effets. Further, it was recently observed that TFMPP, 5-HT1B agonist, elicited profound diuresis and natriuresis when administered intracerebroventricularly(icv). Present study is therefore undertaken to delineate the mechanism involved in the natriuresis and diuresis induced by icv TFMPP, employing the denervated and vagotomized rabbits. The influence of icv TFMPP on the plasma level of ANP was also observed. TFMPP 250 microgram/kg icv produced marked diuresis and natriuresis. Renal hemodynamics showed significant increase only in the first 10-min period after administration and thereafter tended to recover. However, natriuretic action lasted even after the increased renal hemodynamics returned to the control level, suggesting the decreased Na reabsorption in the tubules by humoral natriuretic factors. Systemic blood pressure transiently increased. In rabbits in which one kidney is denervated, with the contralateral intact as the control kidney, the denervated kidney also responded with natriuresis and diuresis like that of the normal rabbit. The contralateral kidney responded with typical diuretic and natriuretic effects, along with the marked increased of renal hemodynamics. The plasma ANP, one of humoral natriuretic factors, increased after administration of icv TFMPP, peaking at about 15min. In bilaterally vagotomized rabbits, the natriuretic and diuretic effects produced by icv TFMPP were greater than that of the normal rabbits. These observations suggest that the natriuresis and diuresis elicited by icv TFMPP result from the inhibition of tubular Na reabsorption mainly through mediation of ANP. It has been also suggested that vagus nerve might exert inhibitory influence on the diuretic action of icv TFMPP, because the renal effects was augmented in the vagotomized rabbits.
Atrial Natriuretic Factor ; Blood Pressure ; Diuresis ; Diuretics ; Hemodynamics ; Kidney ; Natriuresis ; Natriuretic Agents ; Negotiating ; Plasma ; Rabbits* ; Receptors, Serotonin, 5-HT1 ; Receptors, Serotonin, 5-HT3 ; Serotonin 5-HT1 Receptor Agonists ; Vagus Nerve

BACKGROUND: Spinal 5-hydroxytryptamine (5-HT) has been shown to display an antinociceptive effect, which is mediated by 5-HT receptors. Previous studies have revealed the presence of at least four types of 5-HT receptors in the spinal cord. The aim of this study was to assess the role of each spinal 5-HT receptor in the antinociception of intrathecal 5-HT using the formalin test. METHODS: Rats were implanted with lumbar intrathecal catheters. After the administration of 5-HT, formalin-induced nociceptive behavior (flinching response) was observed for 60 min. To further clarify the role of the 5-HT receptors in the antinociception of 5-HT, several antagonists of 5-HT receptors were administered intrathecally 10 min before 5-HT delivery, and formalin was injected 10 min later. RESULTS: Intrathecal 5-HT dose-dependently suppressed flinching during phase 1 and 2 in the formalin test. 5-HT1B (GR 55562), 5-HT2C (N-desmethylclozapine), 5-HT3 (LY-278,584) and 5-HT4 (SDZ-205,557) receptors antagonists reversed this antinociception by 5-HT during both phases in the formalin test. 5-HT1A receptor antagonist (WAY-100635) decreased antinociception by 5-HT in phase 2, but not in phase 1. A 5-HT1D receptor antagonist (BRL 15572) did not antagonize the antinociception of 5-HT in either phases. CONCLUSIONS: Spinal 5-HT1B, 5-HT2C, 5-HT3 and 5-HT4 receptors, but not the 5-HT1D receptor, are involved in the antinociception of serotonin in the facilitated state and in the acute pain evoked by a formalin stimulus. The 5-HT1A receptor seems to play a role in 5-HT-induced antinociception in the facilitated state.
Acute Pain ; Animals ; Catheters ; Formaldehyde ; Pain Measurement ; Rats* ; Receptor, Serotonin, 5-HT1A ; Receptor, Serotonin, 5-HT1D ; Receptors, Serotonin ; Receptors, Serotonin, 5-HT4 ; Serotonin* ; Spinal Cord*

AIMTo study the correlation between 5-HT-induced pain response and the contribution by individual 5-HTR subtypes including 5-HT1R, 5-HT2R and 5-HT3R at the level of peripheral primary afferent.

METHODSThe experiments were done on acutely isolated trigeminal ganglion (TG) neurons using whole-cell patch clamp technique and the nociceptive effect was observed on behavior experiments by intraplantar injection of test drugs.

RESULTSThe majority of cells examined responded to 5-HT in a manner of concentration dependence (10(-6) - 10(-3) mol/) (61.4%, 54/88) and with a fast activating and rapid desensitizing inward current (I(5-HT)), which was thought to be mediated by the activation of 5-HT3R, since it could be blocked by 5-HT3R antagonist ICS 205930 and mimicked by 5-HT3R agonist 2-methyl-5-HT. It was found that I(5-HT) was potentiated by 5-HT2R agonist alpha-methyl-5-HT markedly, while 5-HT1R agonist R-(+)-UH 301 did not. In behavioral experiment performed on conscious rats, intraplantar injection of 5-HT(10(-5), 10(-4) and 10(-3) mol/L) induced an increment of cumulative lifting time first 20 min in a manner of concentration dependence. By dissociating 5-HTR subtypes using their corresponding antagonists (ICS and CYP) the potency order of hindpaw lifting time was identified as follows: 5-HT > 5-HT + ICS > 5-HT + CYP.

CONCLUSIONThe results suggest that in 5-HT-induced nociceptive response at the primary sensory level 5-HT3R may play a role of initiation, but 5-HT2R mediates maintaining and modulatory effect in the processes of nociceptive information convey.

Animals ; Male ; Membrane Potentials ; Pain ; physiopathology ; Patch-Clamp Techniques ; Rats ; Rats, Sprague-Dawley ; Receptors, Serotonin, 5-HT1 ; metabolism ; Receptors, Serotonin, 5-HT2 ; metabolism ; Receptors, Serotonin, 5-HT3 ; metabolism ; Sensory Receptor Cells ; metabolism ; physiology

PURPOSE: The purpose of this study is to investigate in vitro the effects of serotonin on the rat detrusor. In particular, this study examines what drugs inhibit the serotonin-induced detrusor contractions. MATERIALS AND METHODS: Isometric tension changes of isolated rat bladder muscle strips were recorded in an organ bath using a force transducer. Acute effects of serotonin (0.0001-0.01mM) were assessed on resting tension. Electrical field stimulation (EFS), bethanechol (0.0001-0.01mM), ATP (1-3mM) or KCl(63.5-254mM)-induced contractions using application in organ bath were compared with serotonin-induced contractions. In order to examine the action mechanism of serotonin-induced stimulation, EFS, bethanechol, ATP or KCl-induced contraction under serotonin (0.001mM) was assessed and serotonin (0.001 to 0.1mM) was cumulatively added to the organ bath following pre-incubation with propranolol, ketanserine, tropisetron, propiverine, sodium nitroprusside or doxazocin. RESULTS: There are two phases to the serotonin-induced responsean initial transient contraction and a prolonged tonic phase. Serotonin produced a reversible and dose-dependent contraction of the detrusor strips. Responses to bethanechol significantly increased with a concentration of 0.001mM serotonin (p<0.05). There was no effect on the responses to ATP, KCl, or EFS under 0.001mM serotonin. The 5-HT2 receptor is mainly responsible for serotonin-induced contractions of the detrusor (p<0.05), while the 5-HT1 receptor is partially responsible. Doxazocin and propiverine each significantly suppressed the responses to serotonin, while sodium nitroprusside and tropisetron each had no effect (p<0.05). CONCLUSIONS: Because the 5-HT2 antagonist blocked the effect of serotonin-induced bladder contractions and the stimulation of the adrenoreceptors, the 5-HT2 antagonist seems to improve lower urinary tract symptoms.
Adenosine Triphosphate ; Animals ; Baths ; Bethanechol ; Ketanserin ; Lower Urinary Tract Symptoms ; Nitroprusside ; Propranolol ; Rats ; Receptors, Serotonin, 5-HT1 ; Serotonin ; Serotonin 5-HT2 Receptor Antagonists ; Transducers ; Urinary Bladder ; Urinary Bladder, Overactive*

The present study aimed at evaluation of prophylactic efficacy and possible mechanisms of asiaticoside (AS) based standardized extract of Centella asiatica (L.) Urban leaves (INDCA) in animal models of migraine. The effects of oral and intranasal (i.n.) pretreatment of INDCA (acute and 7-days subacute) were evaluated against nitroglycerine (NTG, 10 mg·kg(-1), i.p.) and bradykinin (BK, 10 μg, intra-arterial) induced hyperalgesia in rats. Tail flick latencies (from 0 to 240 min) post-NTG treatment and the number of vocalizations post-BK treatment were recorded as a measure of hyperalgesia. Separate groups of rats for negative (Normal) and positive (sumatriptan, 42 mg·kg(-1), s.c.) controls were included. The interaction of INDCA with selective 5-HT1A, 5-HT1B, and 5-HT1D receptor antagonists (NAN-190, Isamoltane hemifumarate, and BRL-15572 respectively) against NTG-induced hyperalgesia was also evaluated. Acute and sub-acute pre-treatment of INDCA [10 and 30 mg·kg(-1) (oral) and 100 μg/rat (i.n.) showed significant anti-nociception activity, and reversal of the NTG-induced hyperalgesia and brain 5-HT concentration decline. Oral pre-treatment with INDCA (30 mg·kg(-1), 7 d) showed significant reduction in the number of vocalization. The anti-nociceptive effects of INDCA were blocked by 5-HT1A and 5-HT1B but not 5-HT1D receptor antagonists. In conclusion, INDCA demonstrated promising anti-nociceptive effects in animal models of migraine, probably through 5-HT1A/1B medicated action.
Administration, Intranasal ; Administration, Oral ; Animals ; Bradykinin ; Female ; Hyperalgesia ; chemically induced ; prevention & control ; Male ; Migraine Disorders ; chemically induced ; prevention & control ; Models, Animal ; Nitroglycerin ; Nociception ; drug effects ; Plant Leaves ; chemistry ; Pre-Exposure Prophylaxis ; Rats ; Rats, Wistar ; Reaction Time ; Receptors, Serotonin, 5-HT1 ; drug effects ; Serotonin 5-HT1 Receptor Antagonists ; metabolism ; Tail ; physiology ; Triterpenes ; administration & dosage ; pharmacology

This study is to explore the possible mechanisms of the antidepressant-like effect of agmatine. By using two traditional "behavior despair" model, tail suspension test and forced swimming test, we examined the effects of some monoamine receptor antagonists (including beta-adrenergic receptor antagonist propranolol, beta-adrenergic receptor antagonist/5-HT1A/1B receptor antagonist pindolol, alpha2-adrenergic receptor antagonists yohimbine and idazoxan and 5-HT3 receptor antagonist tropisetron) on the antidepressant-like action of agmatine in mice. Activity of adenylate cyclase (AC) in the synapse membrane from rat frontal cortex was determined by radioimmunoassay. Single dose of agmatine (5-40 mg x kg(-1), ig) dose-dependently decrease the immobility time in tail suspension test in mice, indicating an antidepressant-like effect. The effect of agmatine (40 mg x kg(-1), ig) was antagonized by co-administration of beta-adrenergic receptor antagonist/5-HT1A/1B receptor antagonist pindolol (20 mg x kg(-1), ip), alpha2-adrenergic receptor antagonists yohimbine (5-10 mg x kg(-1), ip) or idazoxan (4 mg x kg(-1), ip), but not beta-adrenergic receptor antagonist propranolol (5-20 mg x kg(-1), ip) and 5-HT3 receptor antagonist tropisetron (5-40 mg x kg(-1), ip). Agmatine (5-40 mg x kg(-1), ig) also dose-dependently decrease the immobility time in forced swimming test in mice. The effect of agmatine (40 mg x kg(-1), ig) was also antagonized by pindolol (20 mg x kg(-1), ip), yohimbine (5-10 mg x kg(-1), ip), or idazoxan (4 mg x kg(-1), ip). Incubation of agmatine (0.1-6.4 micromol x L(-1)) with the synaptic membrane extracted from rat frontal cortex activated the AC in a dose-dependent manner in vitro. While the effect of agmatine (6.4 micromol x L(-1)) was dose-dependently antagonized by pindolol (1 micromol x L(-1)) or yohimbine (0.25-1 micromol x L(-1)). Chronic treatment with agmatine (10 mg x kg(-1), ig, bid, 2 w) or fluoxetine (10 mg x kg(-1), ig, bid, 2 w) increased the basic activity, as well as the Gpp (NH)p (1-100 micromol x L(-1)) stimulated AC activity in rat prefrontal cortex. These results indicate that regulation on 5-HT1A/1B and alpha2 receptors, and activation AC in the frontal cortex is one of the important mechanisms involving in agmatine's antidepressant-like action.
Adenylyl Cyclases ; metabolism ; Adrenergic alpha-Antagonists ; pharmacology ; Adrenergic beta-Antagonists ; pharmacology ; Agmatine ; administration & dosage ; pharmacology ; Animals ; Antidepressive Agents ; administration & dosage ; pharmacology ; Behavior, Animal ; drug effects ; Depression ; metabolism ; physiopathology ; Dose-Response Relationship, Drug ; Fenclonine ; pharmacology ; Idazoxan ; pharmacology ; Male ; Mice ; Pindolol ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, Biogenic Amine ; antagonists & inhibitors ; Serotonin 5-HT1 Receptor Antagonists ; Swimming ; Synapses ; enzymology ; Yohimbine ; pharmacology

OBJECTIVES: Recently, polymorphisms of several serotonin genes have been suggested to be associated with suicide, but the results are still unclear. We examined whether the T102C polymorphisms of the serotonin 2A receptor gene and the G861C polymorphisms of the serotonin 1B receptor gene were associated with suicidal behavior using drug intoxication. METHODS: The subjects were 52 patients who visited emergency room with suicidal behaviors. Fifty controls were selected from healthy volunteers matched for sex and age to the suicide subjects. The polymorphisms were analyzed with TaqMan(R) assay using primers based on previous studies. RESULTS: The T102C polymorphism of the serotonin 2A receptor gene showed no significant difference between the suicidal attempters and controls in both genotype and allele frequency analyses(p=0.179 and p=0.422, respectively). There was no statistically significant difference between the suicidal attempters and the controls in the G861C polymorphism of the serotonin 1B receptor gene and any significant effect of the genotype distributions or the allele frequencies was not observed(p=0.092 and p=0.987, respectively). CONCLUSION: These findings suggest that the T102C polymorphism in serotonin 2A receptor gene and the G861C polymorphism in serotonin 1B receptor gene are not related to the susceptibility to suicide attempts using drugs. To clarify the genetic influences of the serotonergic system on suicidal behavior, the polymorphisms of other candidate genes in the serotonergic system should be studied with larger numbers of subjects.
Emergency Service, Hospital ; Gene Frequency ; Genotype ; Healthy Volunteers ; Humans ; Receptor, Serotonin, 5-HT1B ; Receptor, Serotonin, 5-HT2A ; Serotonin* ; Suicide