Desensitization of reticular neurons after ionophoretically applied noradrenalin in rats.

Ionophoretically applied noradrenalin (NA) caused desensitization of about 50% out of a total of 19 investigated reticular neurons in rats which responded to repeated application of NA, although small ejecting currents (1 nA) were used. The desensitization was associated with changes of the pattern of spontaneous discharge activity; this phenomenon was not observed in undesensitized units. Duration of the desensitization (several minutes) showed that NA can induce protracted changes in functional state of neurons.