Humans ; Histamine ; Receptors, Histamine H2 ; Schizophrenia/drug therapy*

Opioid use disorder (OUD) has become a considerable global public health challenge; however, potential medications for the management of OUD that are effective, safe, and nonaddictive are not available. Accumulating preclinical evidence indicates that antagonists of the dopamine D₃ receptor (D₃R) have effects on addiction in different animal models. We have previously reported that YQA14, a D₃R antagonist, exhibits very high affinity and selectivity for D₃Rs over D₂Rs, and is able to inhibit cocaine- or methamphetamine-induced reinforcement and reinstatement in self-administration tests. In the present study, our results illustrated that YQA14 dose-dependently reduced infusions under the fixed-ratio 2 procedure and lowered the breakpoint under the progressive-ratio procedure in heroin self-administered rats, also attenuated heroin-induced reinstatement of drug-seeking behavior. On the other hand, YQA14 not only reduced morphine-induced expression of conditioned place preference but also facilitated the extinguishing process in mice. Moreover, we elucidated that YQA14 attenuated opioid-induced reward or reinforcement mainly by inhibiting morphine-induced up-regulation of dopaminergic neuron activity in the ventral tegmental area and decreasing dopamine release in the nucleus accumbens with a fiber photometry recording system. These findings suggest that D₃R might play a very important role in opioid addiction, and YQA14 may have pharmacotherapeutic potential in attenuating opioid-induced addictive behaviors dependent on the dopamine system.
Rats ; Mice ; Animals ; Analgesics, Opioid ; Dopamine ; Heroin/pharmacology* ; Dopamine Antagonists/pharmacology* ; Receptors, Dopamine D3/metabolism* ; Morphine/pharmacology* ; Behavior, Addictive/drug therapy* ; Self Administration

Insomnia is a common sleep disorder without effective therapy and can affect a person's life. The mechanism of the disease is not completely understood. Hence, there is a need to understand the targets related to insomnia, in order to develop innovative therapies and new compounds. Recently, increasing interest has been focused on complementary and alternative medicines for treating or preventing insomnia. Research into their molecular components has revealed that their sedative and sleep-promoting properties rely on the interactions with various neurotransmitter systems in the brain. In this review, the role of 5-hydroxytryptamine (5-HT) in insomnia development is summarized, while a systematic analysis of studies is conducted to assess the mechanisms of herbal medicines on different 5-HT receptors subtypes, in order to provide reference for subsequent research.
Humans ; Sleep Initiation and Maintenance Disorders/drug therapy* ; Medicine, Chinese Traditional ; Drugs, Chinese Herbal/therapeutic use* ; Plants, Medicinal ; Receptors, Serotonin ; Serotonin

OBJECTIVE: To observe the effect of wheat-grain moxibustion on behavior, 5-hydroxytryptamine (5-HT) and cortisol in the serum, mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hippocampus in rats with hypothyroidism complicated with depression, and to explore the possible mechanism of wheat-grain moxibustion on improving depression in rats with hypothyroidism. METHODS: A total of 32 SPF SD rats were randomly divided into a blank group, a model group, a medication group and a wheat-grain moxibustion group, 8 rats in each group. Except for the blank group, the rats in the remaining groups were treated with intragastric administration of 0.1% propylthiouracil (PTU) suspension at 1 mL/100 g, once a day for 4 weeks to establish the rat model of hypothyroidism, and whether the rats were accompanied with depression-like behavior determined through behavioristics evaluation. The rats in the medication group were intervened with euthyrox at 0.9 mL/100 g, once a day, for 4 weeks; the rats in the wheat-grain moxibustion group were treated with wheat-grain moxibustion at "Dazhui" (GV 14), "Mingmen" (GV 4), "Shenshu" (BL 23) and "Pishu" (BL 20), 7 cones each acupoint, once a day, six times a week for 4 weeks. After the intervention, the depression status was observed by behavioristics test; the contents of thyroid stimulating hormone (TSH), total thyroxine (TT4), 5-HT and cortisol in the serum were detected by ELISA; the protein expressions of MR and GR in hippocampus were detected by Western blot; the expressions of MR mRNA and GR mRNA in the hippocampus were detected by real-time PCR. RESULTS: Before the intervention, compared with the blank group, the scores of open field test (OFT) were decreased and the immobility time of tail suspension test (TST) was prolonged (P<0.05); the serum TSH contents were increased and TT4 contents were decreased (P<0.01) in the other three groups. After the intervention, compared with the model group, the vertical score of OFT was increased and the immobility time of forced swimming test (FST) was prolonged in the medication group (P<0.05), while the scores of three items of OFT were increased (P<0.05, P<0.01), and the immobility time of FST and TST was shortened in the wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the medication group, the immobility time of TST and FST in the wheat-grain moxibustion group was shorter (P<0.05, P<0.01). Compared with the blank group, in the model group, the contents of serum TSH and cortisol were increased (P<0.01, P<0.001), while the contents of serum TT4 and 5-HT were decreased (P<0.01, P<0.001). Compared with the model group, the contents of serum TT4 and 5-HT were increased, while the contents of serum TSH and cortisol were decreased in the medication group and wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the blank group, the protein and mRNA expression of MR, GR in the hippocampus in the model group was decreased (P<0.01, P<0.05, P<0.001); compared with the model group, the protein and mRNA expression of MR in the hippocampus in the medication group were increased (P<0.05), and the protein expression of MR, GR and mRNA expression of MR in the hippocampus in the wheat-grain moxibustion group were increased (P<0.05, P<0.01). Compared with the medication group, the expression of MR mRNA in the wheat-grain moxibustion group was increased (P<0.05). CONCLUSION Wheat-grain moxibustion could significantly improve thyroid function and depression in rats with hypothyroidism. Its mechanism may be related to up-regulating the protein and mRNA expression of MR and GR in the hippocampus, and then affecting the expression of serum cortisol and 5-HT.
Acupuncture Points ; Animals ; Depression/therapy* ; Hippocampus/metabolism* ; Hydrocortisone/metabolism* ; Hypothyroidism/therapy* ; Moxibustion ; RNA, Messenger/metabolism* ; Rats ; Rats, Sprague-Dawley ; Receptors, Glucocorticoid/metabolism* ; Receptors, Mineralocorticoid/metabolism* ; Serotonin ; Thyrotropin/metabolism* ; Triticum/metabolism*

The purpose of this study was to investigate the effects of α₂ adrenergic receptor agonist dexmedetomidine on withdrawal symptoms in alcohol-dependent rats and the underlying mechanism, so as to provide a scientific basis for the treatment of alcohol withdrawal syndrome (AWS). Adult Sprague-Dawley (SD) male rats were orally administered with 6% aqueous alcohol continuously for 28 d to establish alcohol drinking model, and then stopped drinking to induce AWS. Enzyme-linked immunosorbent assay (ELISA) was used to determine the content of norepinephrine (NE) in the locus coeruleus and hippocampus of rats. Dexmedetomidine (5, 10, and 20 μg/kg) was intraperitoneally injected respectively when the rats showed significant AWS. In some rats, α₂ adrenergic receptor antagonist yohimbine was injected into hippocampus in advance. The results showed that, compared with the control group, the 6 h withdrawal group exhibited significantly increased AWS score and amount of repeat drinking. The NE contents in hippocampus and locus coeruleus of the last drinking and the 6 h withdrawal groups were significantly increased compared with those of the control group. Dexmedetomidine intervention significantly decreased AWS score and hippocampus NE content in the 6 h withdrawal group, while yohimbine could reverse these effects of dexmedetomidine. These results suggest that dexmedetomidine might improve the withdrawal symptoms in alcohol-dependent rats via activating α₂ adrenergic receptor.
Adrenergic alpha-2 Receptor Agonists/therapeutic use* ; Alcoholism/drug therapy* ; Animals ; Dexmedetomidine/therapeutic use* ; Hippocampus/metabolism* ; Male ; Norepinephrine ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenergic, alpha-2/metabolism* ; Substance Withdrawal Syndrome/drug therapy* ; Yohimbine/pharmacology*

OBJECTIVE: Dexmedetomidine (DEX), the most specific α ₂-adrenergic receptor agonist widely used for its sedative and analgesic properties, has been reported to upregulate HIF-1α expression to protect hypoxic and ischemic tissues. However, it is largely unclear whether DEX can also upregulate Hypoxia-inducible factor-1 alpha (HIF-1α) expression and its downstream vascular endothelial growth factor-A (VEGFA) in cancer tissues with oxygen-deficient tumor microenvironment. METHODS: We used SMMC-7721 cells, MHCC97-H cells, and a mouse model of orthotopic hepatic carcinoma to explore the effect of DEX on angiogenesis and vasculogenic mimicry (VM) and its mechanism. Under normoxic (20% O ₂) and hypoxic (1% O ₂) conditions, DEX was used to intervene cells, and yohimbine was used to rescue them. RESULTS: The results showed that DEX promoted angiogenesis and VM in human liver cancer cells within a certain dose range, and the addition of yohimbine inhibited this effect. DEX could activate HIF-1α/VEGFA pathway, which was further verified by silencing HIF-1α. Consistently, in vivo results also showed that DEX can up-regulate HIF-1α/VEGFA expression, and enhance the number of VM channels and microvessel density (MVD). CONCLUSION We believe that HIF-1α/VEGFA might be an important signaling pathway by which DEX promotes angiogenesis and VM formation in human hepatocellular carcinoma, whereas α ₂-adrenergic receptor mediation might be the critical mechanisms.
Animals ; Humans ; Mice ; Adrenergic alpha-2 Receptor Agonists/pharmacology* ; Carcinoma, Hepatocellular ; Cardiovascular Physiological Phenomena ; Dexmedetomidine/pharmacology* ; Hypoxia ; Liver Neoplasms/drug therapy* ; Oxygen ; Tumor Microenvironment ; Vascular Endothelial Growth Factor A/genetics* ; Receptors, Adrenergic, alpha-2/metabolism*

Cerebellar Purkinje cells (PCs) exhibit two types of discharge activities: simple spike (SS) and complex spike (CS). Previous studies found that noradrenaline (NA) can inhibit CS and bidirectionally regulate SS, but the enhancement of NA on SS is overwhelmed by the strong inhibition of excitatory molecular layer interneurons. However, the mechanism underlying the effect of NA on SS discharge frequency is not clear. Therefore, in the present study, we examined the mechanism underlying the increasing effect of NA on SS firing of PC in mouse cerebellar cortex in vivo and in cerebellar slice by cell-attached and whole-cell recording technique and pharmacological methods. GABA_A receptor was blocked by 100 µmol/L picrotoxin in the whole process. In vivo results showed that NA significantly reduced the number of spikelets of spontaneous CS and enhanced the discharge frequency of SS, but did not affect the discharge frequency of CS. In vitro experiments showed that NA reduced the number of CS spikelets and after hyperpolarization potential (AHP) induced by electrical stimulation, and increased the discharge frequency of SS. NA also reduced the amplitude of excitatory postsynaptic current (EPSC) of parallel fiber (PF)-PC and significantly increased the paired-pulse ratio (PPR). Application of yohimbine, an antagonist of α2-adrenergic receptor (AR), completely eliminated the enhancing effect of NA on SS. The α2-AR agonist, UK14304, also increased the frequency of SS. The β-AR blocker, propranolol, did not affect the effects of NA on PC. These results suggest that in the absence of GABA_A receptors, NA could attenuate the synaptic transmission of climbing fiber (CF)-PC via activating α2-AR, inhibit CS activity and reduce AHP, thus enhancing the SS discharge frequency of PC. This result suggests that NA neurons of locus coeruleus can finely regulate PC signal output by regulating CF-PC synaptic transmission.
Action Potentials/physiology* ; Animals ; Cerebellar Cortex/metabolism* ; Cerebellum/metabolism* ; Mice ; Norepinephrine/pharmacology* ; Purkinje Cells/metabolism* ; Receptors, Adrenergic, alpha-2/metabolism* ; Receptors, GABA-A/metabolism*

Cortical GABAergic inhibitory neurons are composed of three major classes, each expressing parvalbumin (PV), somatostatin (SOM) and 5-hydroxytryptamine receptor 3A (Htr3a), respectively. Htr3a
Animals ; Interneurons/metabolism* ; Mice ; Neurons/metabolism* ; Parvalbumins/metabolism* ; Receptors, Serotonin, 5-HT3/genetics* ; Serotonin ; Somatostatin/metabolism*

Rabbit Syndrome is an uncommon side effect of antipsychotic treatment. Although it is usually associated with typical antipsychotics, it can also be related to atypical antipsychotics. Anticholinergics are the most accepted treatment approach in treating Rabbit Syndrome. Fluvoxamine is a member of selective serotonin reuptake inhibitors and it is a potent agonist of sigma 1 receptors. In this article, we report a Rabbit Syndrome case who has benefited from fluvoxamine, in terms of both depressive disorder and Rabbit Syndrome; and present the data on the effects of sigma 1 agonist fluvoxamine on numerous movement disorders.
Antipsychotic Agents ; Cholinergic Antagonists ; Depressive Disorder ; Fluvoxamine ; Movement Disorders ; Receptors, sigma ; Serotonin Uptake Inhibitors

The lamina II, also called the substantia gelatinosa (SG), of the trigeminal subnucleus caudalis (Vc), is thought to play an essential role in the control of orofacial nociception. Glycine and serotonin (5-hydroxytryptamine, 5-HT) are the important neurotransmitters that have the individual parts on the modulation of nociceptive transmission. However, the electrophysiological effects of 5-HT on the glycine receptors on SG neurons of the Vc have not been well studied yet. For this reason, we applied the whole-cell patch clamp technique to explore the interaction of intracellular signal transduction between 5-HT and the glycine receptors on SG neurons of the Vc in mice. In nine of 13 neurons tested (69.2%), pretreatment with 5-HT potentiated glycine-induced current (I(Gly)). Firstly, we examined with a 5-HT₁ receptor agonist (8-OH-DPAT, 5-HT(1/7) agonist, co-applied with SB-269970, 5-HT₇ antagonist) and antagonist (WAY-100635), but 5-HT₁ receptor agonist did not increase IGly and in the presence of 5-HT₁ antagonist, the potentiation of 5-HT on I(Gly) still happened. However, an agonist (α-methyl-5-HT) and antagonist (ketanserin) of the 5-HT₂ receptor mimicked and inhibited the enhancing effect of 5-HT on I(Gly) in the SG neurons, respectively. We also verified the role of the 5-HT₇ receptor by using a 5-HT₇ antagonist (SB-269970) but it also did not block the enhancement of 5-HT on I(Gly). Our study demonstrated that 5-HT facilitated I(Gly) in the SG neurons of the Vc through the 5-HT₂ receptor. The interaction between 5-HT and glycine appears to have a significant role in modulating the transmission of the nociceptive pathway.
Animals ; Glycine ; Mice ; Neurons ; Neurotransmitter Agents ; Nociception ; Patch-Clamp Techniques ; Receptors, Glycine ; Serotonin ; Signal Transduction ; Substantia Gelatinosa