Voltage-sensitive calcium channel blockade

Malmberg, A.B. and Yaksh, T.L. Voltage-sensitive calcium channels in spinal nociceptive processing Blockade of N- and P-type channels inhibits formalin-induced nociception, J. Neurosci. 1994, 14, 4882-4890. 

An action potential in the presynaptic fiber propagates into the synaptic terminal and activates voltage-sensitive calcium channels in the membrane of the terminal (Figure 6-3). The calcium channels responsible for the release of transmitter are generally resistant to the calcium channelblocking agents discussed in Chapter 12 Vasodilators the Treatment of Angina Pectoris (verapamil, etc) but are sensitive to blockade by certain marine toxins and metal ions (Tables 12-4 and 21-1). Calcium flows into the terminal, and the increase in intraterminal calcium concentration promotes the fusion of synaptic vesicles with the presynaptic membrane. The transmitter contained in the vesicles is released into the synaptic cleft and diffuses to the receptors on the postsynaptic... 

CNS side effects may be due to excessive blockade of voltage-sensitive calcium channels... 

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