Octopamine and proctolin mimic spontaneous membrane depolarisation inLucilia larvae

Summary Octopamine and proctolin at concentrations below 10^–8 M reversibly induce a spontaneous rhythmic depolarization which occurs in body-wall muscles ofLucilia larvae. The effect appears to be postsynaptic and mediated by receptors specific for each substance.This work was supported by NIEHS grant No. ES00814 and EPA grant No. R804345.     

Peptidergic co-transmission inAplysia: Functional implications for rhythmic behaviors

Despite their ubiquitous presence in the central and peripheral nervous systems, the behavioral functions of peptide co-transmitters remain to be elucidated. The marine molluscAplysia, whose simple nervous system facilitates the study of the neural basis of behavior, was used to investigate the role of peptidergic co-transmission in feeding behavior. Several novel modulatory neuropeptides were purified, and localized to identified cholinergic motorneurons. Physiological and biochemical studies demonstrated that these peptides are released when the motorneourons fire at frequencies that occur during normal behavior, and that the peptides modify the relationship between muscle contraction amplitude and relaxation rate so as to maintain optimal motor output when the intensity and frequency of feeding behavior change.     

Differences in in vitro incorporation of tritiated deoxycytidine and tritiated thymidine into human lymphocytes

Summary Human lymphocytes stimulated in vitro by PHA or PWM incorporate³H-CdR into DNA, but less well than³H-TdR. More³H-CdR is incorporated in populations enriched for T cells. No³H-CdR is used by cells stimulated by lipopolysaccharides under circumstances in which³H-TdR is incorporated. We conclude that human T cells and B cells differ in their ability to use³H-CdR.