strychnine and gelsemine

To establish a LC-MS/MS method which is accurate and sensitive for determination of koumine, gelsemine, and gelsenicine in biological samples and to verify the method.. Strychnine was used as internal standard. Analytes in blood, urine and liver with 1% sodium hydroxide solution were extracted by ethyl acetate. Chromatographic separation was achieved on a ZORBAX SB-C₁₈ column （150 mm×2.1 mm, 5 μm）, and gradient elution was performed with the buffer solution of methanol-20 mmol/L ammonium acetate （including 0.1% formic acid and 5% acetonitrile） as mobile phase. Qualitative and quantitative analysis was performed in the multiple reaction monitoring mode coupled with an electrospray ionization source under positive ion mode（ESI⁺）.. The method is selective, sensitive and suitable for simultaneous determination of koumine, gelsemine and gelsenicine in body fluids and tissues, which offering technical support for clinical diagnosis and treatment and forensic toxicological analysis of

Topics: Alkaloids; Chromatography, High Pressure Liquid; Chromatography, Liquid; Forensic Toxicology; Formates; Humans; Indole Alkaloids; Liver; Reproducibility of Results; Strychnine; Tandem Mass Spectrometry

The present study examined the antinociceptive effects of gelsemine, the principal alkaloid in Gelsemium sempervirens Ait. A single intrathecal injection of gelsemine produced potent and specific antinociception in formalin-induced tonic pain, bone cancer-induced mechanical allodynia, and spinal nerve ligation-induced painful neuropathy. The antinociception was dose-dependent, with maximal inhibition of 50% to 60% and ED50 values of 0.5 to 0.6 μg. Multiple daily intrathecal injections of gelsemine for 7 days induced no tolerance to antinociception in the rat model of bone cancer pain. Spinal gelsemine was not effective in altering contralateral paw withdrawal thresholds, and had only a slight inhibitory effect on formalin-induced acute nociception. The specific antinociception of gelsemine in chronic pain was blocked dose-dependently by the glycine receptor (GlyR) antagonist strychnine with an apparent ID50 value of 3.8 μg. Gelsemine concentration-dependently displaced H(3)-strychnine binding to the membrane fraction of rat spinal cord homogenates, with a 100% displacement and a Ki of 21.9μM. Gene ablation of the GlyR α3 subunit (α3 GlyR) but not α1 GlyR, by a 7-day intrathecal injection of small interfering RNA (siRNA) targeting α3 GlyR or α1 GlyR, nearly completely prevented gelsemine-induced antinociception in neuropathic pain. Our results demonstrate that gelsemine produces potent and specific antinociception in chronic pain states without induction of apparent tolerance. The results also suggest that gelsemine produces antinociception by activation of spinal α3 glycine receptors, and support the notion that spinal α3 glycine receptors are a potential therapeutic target molecule for the management of chronic pain.

Topics: Alkaloids; Analgesics; Animals; Binding, Competitive; Bone Neoplasms; Chronic Pain; Gelsemium; Glycine Agents; Injections, Intraventricular; Injections, Spinal; Ligation; Male; Neuralgia; Pain Measurement; Postural Balance; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; Receptors, Glycine; RNA, Small Interfering; Spinal Cord; Spinal Nerves; Strychnine

The neurosteroid allopregnanolone (3alpha,5alpha-THP) is well characterized as a potentially therapeutic molecule which exerts important neurobiological actions including neuroprotective, antidepressant, anxiolytic, anesthetic and analgesic effects. We have recently observed that neurons and glial cells of the rat spinal cord (SC) contain various key steroidogenic enzymes such as 5alpha-reductase and 3alpha-hydroxysteroid oxido-reductase which are crucial for 3alpha,5alpha-THP biosynthesis. Furthermore, we demonstrated that the rat SC actively produces 3alpha,5alpha-THP. As the key factors regulating neurosteroid production by nerve cells are unknown and because glycine is one of the pivotal inhibitory neurotransmitters in the SC, we investigated glycine effects on 3alpha,5alpha-THP biosynthesis in the rat SC. Glycine markedly stimulated [(3)H]-progesterone conversion into [(3)H]3alpha,5alpha-THP by SC slices. The alkaloid strychnine, well-known as a glycine receptor (Gly-R) antagonist, blocked glycine stimulatory effect on 3alpha,5alpha-THP formation. Gelsemine, another alkaloid containing the same functional groups as strychnine, increased 3alpha,5alpha-THP synthesis. The stimulatory effects of glycine and gelsemine on 3alpha,5alpha-THP production were additive when the two drugs were combined. These results demonstrate that glycine and gelsemine, acting via Gly-R, upregulate 3alpha,5alpha-THP biosynthesis in the SC. The data also revealed a structure-activity relationship of the analogs strychnine and gelsemine on neurosteroidogenesis. Possibilities are opened for glycinergic agents and gelsemine utilization to stimulate selectively 3alpha,5alpha-THP biosynthetic pathways in diseases evoked by a decreased neurosteroidogenic activity of nerve cells.

Topics: Alkaloids; Animals; Dose-Response Relationship, Drug; Drug Antagonism; Drug Synergism; Glycine; Glycine Agents; Male; Molecular Structure; Neuroglia; Neurons; Organ Culture Techniques; Pregnanolone; Rats; Rats, Sprague-Dawley; Receptors, Glycine; Spinal Cord; Strychnine