Stimulation is necessary for the development of tolerance to a neuronal effect of ethanol.

Ethanol accelerates the decay of post-tetanic potentiation at an identified synapse in Aplysia. We have previously shown that with repeated exposures the ethanol effect diminishes, a development termed "tolerance." Here we present evidence that the establishment of tolerance depends on a adequate stimulation of the presynaptic terminal in the presence of ethanol.

Separate serotonin and dopamine receptors modulate the duration of post-tetanic potentiation at an Aplysia synapse without affecting other aspects of synaptic transmission.

We have studied the effect of the biogenic amines, serotonin and dopamine, on post-tetanic potentiation (PTP) at an identified synapse in the abdominal ganglion of Aplysia californica. We found that: (1) 10(-7) M perfused serotonin doubles the rate constant of decay of PTP. The effect is specific in that neither the size of the non-potentiated (isolated) EPSP nor the amplitude of PTP is affected.

Heterosynaptic stimulation modulates the duration of post-tetanic potentiation at an Aplysia synapse without affecting other aspects of synaptic transmission.

Repetitive stimulation of an axon in the right visceropleural connective to the abdominal ganglion of Aplysia californica produces post-tetanic potentiation (PTP) of a unitary monosynaptic EPSP recorded from cell R15. PTP decays within one half hour following cessation of repatitive stimulation. Stimulation of the left visceropleural connective speeds the rate of decay of PTP, but does not affect the amount of potentiation which is developed or the size of the non-potentiated EPSP.

The amplitude of post-tetanic potentiation of the EPSP RC1-R15 in Aplysia is modulated by environmental parameters.

Evidence is presented that the EPSP called RC1-R15, which is recorded from cell R15 of the abdominal ganglion of Aplysia californica upon appropriate stimulation of the right connective, is endogenously active. In previous studies we showed that after repetitive stimulation the amplitude of this EPSP increases and then slowly decays over many minutes, a phenomenon called post-tetanic potentiation (PTP). The rate of endogenous firing of this EPSP varies with time of day and tonicity of the animal's external environment.

Cross-tolerance to effect of ethanol and temperature in Aplysia: preliminary observations.

Reporting an unexpected finding, this article suggests a bidirectional cross-tolerance between ethanol-tolerant and temperature-adapted preparations may be a widespread phenomenon. Further investigation of these findings may provide useful insight into the nature of the specific membrane changes in alcohol tolerance.