How does cocaine alter the normal mechanism of neurotransmission?
How does cocaine alter the normal mechanism of neurotransmission?
The correct option is D The synaptic vesicles release dopamine but it is unable to bind on the reuptake pump
When an impulse arrives at the synaptic knob, the synaptic vesicles at the presynaptic neuron, release dopamine in the synaptic cleft. Here, dopamine binds to the receptor located at the postsynaptic neuron and transmits a signal. Thus, a neuron is polarized and the impulse is transmitted. After transmission, dopamine detaches from the receptor, enters a channel called reuptake pump and returns to the synaptic knob. But certain drugs, like cocaine, interrupt the normal mechanism of dopamine. When cocaine reaches the synaptic cleft, it gets attached to the reuptake pump and blocks it completely. Now, as the impulse arrives at the synaptic knob, the vesicles release dopamine into the cleft. Dopamine transmits the signal but is unable to return to the presynaptic neuron because the reuptake pump is blocked by cocaine. Thus dopamine collects in the cleft, elevating the concentration of dopamine in the synaptic cleft. Such buildup of dopamine causes continuous stimulation of the postsynaptic neuron. Thus, excess polarization of neuron occurs, increasing the intensity of the impulse.
When an impulse arrives at the synaptic knob, the synaptic vesicles at the presynaptic neuron, release dopamine in the synaptic cleft. Here, dopamine binds to the receptor located at the postsynaptic neuron and transmits a signal. Thus, a neuron is polarized and the impulse is transmitted. After transmission, dopamine detaches from the receptor, enters a channel called reuptake pump and returns to the synaptic knob. But certain drugs, like cocaine, interrupt the normal mechanism of dopamine. When cocaine reaches the synaptic cleft, it gets attached to the reuptake pump and blocks it completely. Now, as the impulse arrives at the synaptic knob, the vesicles release dopamine into the cleft. Dopamine transmits the signal but is unable to return to the presynaptic neuron because the reuptake pump is blocked by cocaine. Thus dopamine collects in the cleft, elevating the concentration of dopamine in the synaptic cleft. Such buildup of dopamine causes continuous stimulation of the postsynaptic neuron. Thus, excess polarization of neuron occurs, increasing the intensity of the impulse.
