Regular firing patterns of suprachiasmatic neurons maintained in vitro.
Cells of the suprachiasmatic nucleus (SCN) recorded in vitro display a characteristic firing pattern. Unlike many other central neurons, they have the ability to fire at a constant low rate with fixed interspike interval. This regularity is most pronounced at firing rates above 3-5 spikes/s. Spontaneous firing below 3 spikes/s was less regular but became increasingly regular as the firing rate was increased. Similarly, regular discharges became irregular when the firing rate was reduced below 3-5 spikes/s. The mean spontaneous firing rate was 5.6 +/- 1.6, range less than 1 to 12 spikes/s and cells were resistant to attempts to increase their rate of firing beyond 15-20 spikes/s. Statistical analysis showed that the firing patterns of all the cells studied formed a single continuous population in terms of their interspike interval distributions, and that these distributions were a function of the firing rate. Addition of either of two commonly used anesthetics, urethane or sodium pentabarbitone, disrupted previously stable, regular activity.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D046508:Culture Techniques; D005260:Female; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D010424:Pentobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000502:physiology*; D014520:Urethane / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D005971:Glutamates; D014520:Urethane; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D010424:Pentobarbital