REGULATION OF NEURON CHOLINORECEPTOR PLASTICITY OF HELIX-LUCORUM BY 2ND-MESSENGERS AND OPIOIDS

The rhythmical local ionophoretic applications of acetylcholine (ACh) to the somatic membrane of Helix lucorum identified neurons evokes the reversible depression of the ACh-induced response which shows cholino receptor (ChR) desensitization. ChR desensitization is regulated not b y one but by several known second messengers and G-proteins, The endog enous opioids perform the excitation or inhibitory tonic control of th e membrane potential in some neurons constantly activating the ionotro pic opiate receptors, The direction of neuron ChR desensitization modu lation by opioids depends on the type of the activated modulatory opia te receptors (mu or kappa) on the neuron membrane. Second messengers a re involved in intracellular mechanism of modulation of the ChR desens itization by opiate kappa-agonist bremazocine.