毒理性
Gelsemine 具有与士的宁类似的机制和作用,可以引起痉挛。士的宁是一种神经毒素,作为甘氨酸和乙酰胆碱受体的拮抗剂。它主要影响脊髓中控制肌肉收缩的 motor nerves。神经冲动的触发是在神经的一端,通过神经递质与受体的结合。在存在神经抑制剂(如甘氨酸)的情况下,必须结合更多的兴奋性神经递质到受体上,才能产生动作电位。甘氨酸主要作为脊髓和大脑中甘氨酸受体的激动剂,这是一种配体门控的氯离子通道。这个氯通道允许负电荷的氯离子进入神经元,导致超极化,使膜电位远离阈值。士的宁是甘氨酸的拮抗剂,这意味着它与同一受体结合,阻止甘氨酸对突触后神经元的抑制作用。因此,动作电位可以在较低的兴奋性神经递质水平下被触发。当抑制信号被阻止时,motor neurons 会更容易被激活,受害者将出现痉挛性肌肉收缩。士的宁与乙酰胆碱结合蛋白(AChBP)复合物的结构。士的宁也是乙酰胆碱受体的拮抗剂,已知与甘氨酸受体同源。(维基百科)
Gelsemine has convulsant effects with a similar mechanism of action to strychnine. Strychnine is a neurotoxin which acts as an antagonist of glycine and acetylcholine receptors. It primarily affects the motor nerves in the spinal cord which control muscle contraction. An impulse is triggered at one end of a nerve by the binding of neurotransmitters to the receptors. In the presence of a neuroinhibitor, such as glycine, a greater quantity of excitatory neurotransmitters must bind to receptors before there will be an action potential generated. Glycine acts primarily as an agonist of the glycine receptor, which is a ligand-gated chloride channel in neurons located in the spinal cord and in the brain. This chloride channel will allow the negatively charged chloride ions into the neuron, causing a hyperpolarization which pushes the membrane potential further from threshold. Strychnine is an antagonist of glycine, which means it binds to the same receptor, preventing the inhibitory effects of glycine on the postsynaptic neuron. Therefore, action potentials are triggered with lower levels of excitatory neurotransmitters. When the inhibitory signals are prevented, the motor neurons do will be more easliy activated and the victim will have spastic muscle contractions. Structure of strychnine in complex with ACh binding protein (AChBP). Strychnine is also an antagonist for acetylcholine receptors, which is known to be homologous to the glycine receptor. (Wikipedia)
来源:Toxin and Toxin Target Database (T3DB)