Low Spontaneous Discharge Rates Research Articles

The spontaneous release of transmitter from insect nerve terminals as predicted by the negative binomial theorem.

1. In the retractor unguis muscles of Periplaneta americana and Blaberus giganteus, the rate of spontaneously occurring miniature potentials from nerve-muscle synapses associated with the ;white' muscle fibres was greater than that observed in the ;red' muscle fibres.2. In 5% of the intracellular recordings, particularly from the ;white' fibres, short ;bursts' of relatively high (20-100 sec(-1)) rates of m.e.p.p.s occurred infrequently in an unpredictable manner. This bursting phenomenon was not observed in extracellular recordings of the miniature potential discharge.3. Rigorous statistical analyses indicated that the spontaneous mode of transmitter release at cockroach retractor unguis muscle fibres was predictable by the negative binomial theorem with a 90% reliability.4. Perfusion of nerve-muscle preparations with high Mg(2+) salines resulted in low spontaneous discharge rates which were characterized by a negative binomial distribution.5. The fit of the data to the negative binomial theorem implied some mutual interaction between those processes responsible for the spontaneous release of transmitter from cockroach nerve terminals.

Activity patterns of catecholamine-containing pontine neurons in the dorso-lateral tegmentum of unrestrained cats.

AbstractSingle catecholamine‐containing neurons in the dorso‐lateral pontine tegmentum were recorded in unanesthetized, freely behaving cats. Microscopic lesions were made on each recorded unit and subsequently identified for catecholamines by fluorescence histochemical analysis. The majority of the NE‐containing neurons exhibited low spontaneous discharge rates in quiet wakefulness and in slow wave sleep. In paradoxical sleep, the medially located NE‐containing neurons tend to exhibit ursting discharges which are closely related to individual PGO waves. The laterally or dorsally situated NE units fire more slowly and tend to derease their firing activity during paradoxical sleep. Tonically active, relatively fast NE‐containing units were also found. Often, those neurons showed greatly increased activity before the cat awoke from either slow wave sleep or paradoxical sleep, with activity persisting during the early moments of waking. The combination of histochemical and electrophysiologic methods proved essential for correlating neurochemistry and function within the heterogeneous NE‐containing nuclei of the cat pons.