• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.315-319
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• 2011

Galanin (Gal) is a 29-amino-acid neuropeptide which is expressed in superior cervical ganglion (SCG) neurons and plays a trophic role in the adult animal and acts as an inhibitory modulator of cholinergic and noradrenergic neurotransmission. Whether activation or inhibition of alpha-adrenoreceptors infl uences Gal mRNA expression in SCG neurons remains unknown. Here, we have evaluated the possible regulation of Gal mRNA expression with acute (4 h) and chronic (4 days) stimulation of alpha 1- and alpha 2-adrenoreceptor agonists or antagonists in primary cultured SCG neurons. The results showed that the amount of Gal mRNA expression in cultured SCG neurons increased signifi cantly after chronic stimulation with alpha 2-adrenoreceptor antagonist yohimbine compared with control SCG neurons at the same time point, whereas the amount of Gal mRNA expression decreased signifi cantly after chronic stimulation with alpha 2-adrenoreceptor agonist clonidine as compared with that in control group. All these effects were not dose-dependent on the administration of alpha 2-adrenoreceptor agonist clonidine or alpha 2-adrenoreceptor antagonist yohimbine. Alpha 1-adrenoreceptor agonist phenylephrine or antagonist prazosin chronic stimulation did not have effects on Gal mRNA expression. Acute exposure of these agents did not have effects on Gal mRNA expression. The present study showed that Gal may be regulated by activation or inhibition of alpha 2-adrenoreceptors, but not alpha 1-adrenoreceptors in sympathetic neurons.

• Journal of Korean Neurosurgical Society
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• v.47 no.6
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• pp.420-423
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• 2010

Objective : Peripheral nerve injury often leads to neuropathic pain, which is characterized by burning pain, allodynia, and hyperalgesia. The role of the sympathetic nervous system in neuropathic pain is a complex and controversial issue. It is generally accepted that the alpha adrenoreceptor (AR) in sympathetic nerve system plays a significant role in the maintenance of pain. Among alpha adrenoreceptor, alpha-1 receptors play a major role in the sympathetic mediated pain. The primary goal of this study is to test the hypothesis that sympathetically maintained pain involves peripheral alpha-2 receptors in human. Methods : The study was a randomized, prospective, double-blinded, crossover study involving twenty patients. The treatments were : Yohimbine (30 mg mixed in 500 mL normal saline), and Phentolamine (1 mg/kg in 500 mL normal saline) in 500 mL normal saline at 70 mL/hr initially then titrated. The patients underwent infusions on three different appointments, at least one month apart. Thus, all patients received all 2 treatments. Pain measurement was by visual analogue scale, neuropathic pain questionnaire, and McGill pain questionnaire. Results : There were significant decreases in the visual analogue scale, neuropathic score, McGill pain score of yohimnine, and phentolamine. Conclusion : We conclude that alpha-2 adrenoreceptor, along with alpha-2 adrenoreceptor, may be play role in sympathetically maintained pain in human.

• Korean Journal of Biological Psychiatry
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• v.22 no.4
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• pp.179-186
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• 2015

Objectives Adrenergic alpha 1 and 2 receptors work as pathways to control the serotonergic neuron moderation and mirtazapine acts as antagonist of these receptors. The adrenoreceptor alpha 1a (ADRA1A) gene, which encodes adrenergic alpha 1 receptor, has Arg-347Cys genetic polymorphism and the polymorphism has strong relationship with many neuro-psychiatric diseases. In this study, we explored the relationship between ADRA1A R347C polymorphism and mirtazapine treatment response in Koreans with major depression. Methods 352 patients enrolled in this study, and the symptoms were evaluated by 17-item Hamilton Depression Rating (HAMD-17) scale. After 1, 2, 4, 8, and 12 weeks of mirtazapine treatment, the association between ADRA1A R347C polymorphism and remission/response outcomes was evaluated. Results Treatment response to mirtazapine was significantly better in T allele carriers than C allele homozygotes after 12 weeks of mirtazapine monotherapy. The percentile decline of HAMD-17 score in T allele carriers was larger than that of C allele homozygotes. ADRA1A R347C genotypes were not significantly associated with remission. Conclusions The result showed that treatment response to mirtazapine was significantly associated with ADRA1A R347C genetic polymorphism. T allele carriers showed better treatment response than C allele homozygotes. It can be supposed that T allele carriers have a trend of better treatment response to mirtazapine monotherapy.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.26-38
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• 1996

In a normal state, sympathetic efferent activity does not elicit discharges of sensory neurons, whereas it becomes associated with and excites sensory neurons in a pathophysiological state such as injury to a peripheral nerve. Although this sympathetic-sensory interaction is reportedly adrenergic, involved subtypes of adrenoreceptors are not yet clearly revealed. The purpose of this study was to determine which adrenorceptor subtypes were involved in sympathetic-sensory interaction that was developed in rats with an experimental peripheral neuropathy. Using rats that received a tight ligation of one or two of L4-L6 spinal nerves 10~15 days previously, a recording was made from afferent fibers in microfilaments teased from the dorsal root that was in continuity with the ligated spinal nerve. Electrical stimulation of sympathetic preganglionic fibers in T13 or L1 ventral root (50 Hz, 2-5 mA. 0.5 ms pulse duration, 10 sec) was made to see if the activity of recorded afferents was modulated. About half of afferents showing spontaneous discharges responded to sympathetic stimulation, and had the conduction velocities in the A-fiber range. Most of the sympathetically induced afferent responses were excitation. This sympathetically induced excitation occurred in the dorsal root ganglion (DRG), and was blocked by yohimbine (${\alpha}_2$ blocker), neither by propranolol ($\beta$ blocker) not by prazosine (${\alpha}_1$ blocker). The results suggest that after spinal nerve ligation, sympathetic efferents interact with sensory neurons having A-fiber axons in DRG where adrenaline released from sympathetic nerve endings excites the activity of sensory neurons by acting on 2-adrenoreceptors. This 2-adrenoreceptor mediated excitation of sensory neurons may account for sympathetic involvement in neuropathic pain.

• YAKHAK HOEJI
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• v.54 no.4
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• pp.300-308
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• 2010

Adrenoceptor has been considered to be an important target in psychiatric disorders. Based on x-ray structures of bovine rhodopsin, we established homology model of ${\alpha}_{2c}$-adrenoceptor (ADA2C_rat) and then analyzed docking from binding model of receptor-ligand complex with high-active compound No.29 in tricyclic isoxazole analogues (1-30). We observed that the N (1.907 $\AA$) and O (1.712 $\AA$) atoms of isoxazole ring on the docked ligand (No.29) formed H-bonding interaction with O-H of Ser5.32 and carmeron phenyl ring centroid of tricyclic isoxazole formed $\pi-\pi$ interaction at 3.342 $\AA$ distance with phenyl ring centroid of Phe6.52. According to predictions of blood-brain distribution (logBB) through penetration of blood-brain barrie (BBB) and polar surface area (PSA) of the ligands, the high-active compound No.29 has values of logBB=-0.203, PSA=67.50, respectively. These results suggest that the high-active compound No.29 is a novel anti-depressant with the characteristics such as dopamine and serotonin.

• Journal of Dental Anesthesia and Pain Medicine
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• v.16 no.1
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• pp.55-59
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• 2016

Dental treatment under sedation requires various sedation depths depending on the invasiveness of the procedure and patient drug sensitivity. Inappropriate sedation depth may cause patient discomfort or endangerment. For these reasons, patient-controlled sedation (PCS) pumps are commonly used. Patients are able to control the sedation depths themselves by pushing the demand button after the practitioner sets up the bolus dose and lock-out time. Dexmedetomidine is an ${\alpha}$-2 adrenoreceptor agonist with sedative, analgesic, and anxiolytic properties. It has been widely used for sedation for its minimal respiratory depression; however, there are few studies on PCS using dexmedetomidine. This study assessed the applicability of dexmedetomidine to PCS.

• The Korean Journal of Pharmacology
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• v.13 no.2
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• pp.49-59
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• 1977

Adrenergic receptors are now classified into alpha type and beta type These adrenergic receptors are distributed in various tissue in different patterns. Therefore, the adrenergic response of a certain tissue may be different from those of the other tissues, and such differences may exist among various species of animals. In this paper, the authors attempt to reevaluate the effect of epinephrine on the isolated atria, aortic strips, and vas deferenses of rabbits preincubated with alpha receptor blockades (ergotamine and dibenamine) and beta receptor blockades (propranolol and dichloroisoproterenol) in Locke-Ringer bathing medium. The results obtained were summarized as follows; 1) The dose dependent responses of isolated atria to epinephrine were significantly inhibited by propranolol and dichloroisoproterenol, and slightly inhibited by dibenamine, but not affected by ergotamine. 2) The dose dependent responses of excised aortic strips to epinephrine were significantly inhibited by ergotamine and dibenamine, but the responses were slightly potentiated by propranolol, and significantly by dichloroisoproterenol. 3) The dose dependent responses of isolated vas deferenses to epinephrine were significantly inhibited by ergotamine and dibenamine, but slightly potentiated by propranolol and dichloroisoproterenol.

• YAKHAK HOEJI
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• v.29 no.4
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• pp.165-175
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• 1985

It has been reported that clonidine is $\alpha_2$-adrenergic agonist, potnet new hypotensive drug in human with low dose. The change in blood pressure is implicated in the concentration, release, uptake and metabalism of catecholamine and activity of catecholamine synthesizing enzyme in specific brain areas. Thus the experiment was set up to investigate the effect on the enzyme activity of clonidine alone and that of clonidine pretreated with imipramine or tranylcypromine by measuring activity of the Dopa-forming enzyme, tyrosine hydroxylase (TH) and epinephrine forming enzyme, phenylethanolamine-N-methyl transferase (PNMT) in brain and adrenal gland. The TH activity in brainstem and substantia nigra is decreased by intraperitoneally administered clonidine 0.1mg/kg twice a day for 5 days, but increased in the rats pretreated with imipramine 10mg/kg intraperitoneally given 26 hrs and 5 hrs before decaptitation. However the TH activity in all regions of brain is increased in rats pretreated with tranylcypromine 10mg/kg intraperitoneally twice a day for 5 days. The effect of clonidine on TH activity is due to inhibition release of norepinephrine by activation of presynaptic $\alpha_2$-adrenoreceptor, axon terminal result in the decrease of TH activity in brain. The increasing of TH activity in brain results in attenuation of the role of clonidine by pretreated with imipramine or tranylcypromine in rats. The activity of PNMT was not significantly affected by clonidine, imipramine and tranylcypromine in adrenal gland.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.156-163
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• 2000

Background: Peripheral nerve injury sometimes leads to chronic neuropathic pain such as causalgia. A subset of patients with causalgia have a sympathetically maintained pain which is often evoked by cooling stimuli. However, our knowledge on adrenergic receptor types responsible for cold-evoked pain that is sympathetically dependent is lacking. The present study was conducted to investigate subtypes of adrenoceptors involved in mediating cold-evoked pain that developed following peripheral nerve injury. Methods: Neuropathic surgery was performed by a unilateral ligation of L5 and L6 spinal nerves of rats. Behavioral sign of cold-evoked pain was examined for 5 min by measuring cumulative duration of time that the rat lifted its foot off a metal plate held at cold temperature ($5^{\circ}C$). Whether cold-evoked pain behavior was affected by antagonists of various subtypes of adrenoceptors, which were administered intraperitoneally before and after the ligation, was investigated. Results: After ligation, duration of foot lifting on the ligated side at cold temperature increased as compared to the pre-operative period. This increase maintained for the entire 40-day test period. Pretreatment with alpha-antagonist phentolamine produced a suppression of cold-evoked pain behavior that was not affected by beta-antagonist propranolol pretreatment. Prazosin, alpha-1 antagonist, suppressed cold- evoked pain behavior when treated either before or after nerve ligation. On the other hand, alpha-2 antagonist yohimbine was without effect on cold-evoked pain behavior whether it was treated before or after the ligation. Conclusions: The results suggest that peripheral nerve injury develops cold-evoked pain that is sympathetically dependent, and that alpha-1 adrenoreceptor plays a critical role for the generation of this type of pain in its initiation as well as maintenance.

• Biomolecules & Therapeutics
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• v.13 no.2
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• pp.90-94
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• 2005

Prazosin hydrochloride is an antihypertensive drug with selective ${\alpha}_1$-adrenoreceptor blocking effects. A simple high performance liquid chromatographic method has been developed and validated for the quantitative determination of prazosin in human plasma. A reversed-phase C18 column was used for the separation of prazosin and terazosin (internal standard) with a mobile phase composed of water, acetonitrile and triethylamine(75:25:0.1, V/V;pH5.0) at a flow rate of 1.5 ml/min. the fluorescence detector was set at excitation and emissionwavelengths of 250 and 370 nm, respectively. Intra-and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification of 0.5 ng/ml. Good recovery (>80%) was seen in plasma. Prazosin was stable in human plasma under various storage conditions. This method was used successfully for a pharmacokinetic study in plasma after oral administration of a single 2-mg dose as prazosin base to 16 healthy volunteers. The maximum plasma concentration of prazosin was 23.1 ${\pm}$ 16.5 ng/ml at 2.1 h, and the mean area under the curve and elimination half-life were calculated to be 108.4 ${\pm}$ 74.2 ng ${\cdot}$hr/ml and 2.5 ${\pm}$ 0.6 h, respectively.