GENERAL AND SIGNAL-SPECIFIC LONG-TERM NOC ICEPTIVE SENSITIZATION IN HELIX-LUCORUM SNAIL

Neurophysiological and behavioural correlates of the long-term sensiti zation were investigated im Helix lucorum snail Application of 10% qui nine solution on the snail's head initiated a long-term (for mom than 24 hours) facilitation of defensive reactions. The behavioural effects correlated with the changes in evoked and spontaneous activity of L-P Pl1 neurons, i. e., facilitation of synaptic components in responses. To testing stimulation increase in membrane excitability and depolariz ation Efficacy of sensitization depended an the duration of the experi mental procedure. After daily training site-specific acid modality-spe cific effects dominated (i. e., more expressed facilitation of respons es to testing stimulation of the sensitized body site than that of the other sites or to testing stimulation of the same modality as sensiti zing stimulation). After 3 days of training the effects of general sen sitization were predominantly observed, i. e., facilitation of neurona l responses to stimulation of different modalities and body sites, dep olarization of the membrane and increase in its excitability.