A new efferent pathway in the cockroach CNS

Riassunto Viene descritta una nuova via efferente della catena ganglionare diPeriplaneta americana, che origina nel 1° ganglio addominale, raggiunge i nervi cercali (NXI) ed è interrotta da sinapsi in ciascuno dei sei gangli addominali. Vengono riferiti la velocità di conduzione nei connettivi ed i tempi di trasmissione a livello dei gangli.     

Synthesis of 5-hydroxytryptamine in the American cockroach

Zusammenfassung Biologischer und chemischer Nachweis von 5-Hydroxytryptamin im Nervengewebe vonPeriplaneta americana und erster Bericht über die Synthese: Die Substanz konnte in Geschlechtsdrüsen, Eingeweiden und Malpighischen Gefässen nicht positiv identifiziert werden. Sie wird bei enthirnten und bauchmarklosen Tieren zu 5-Hydroxytryptamin decarboxyliert.     

Volatile sex pheromone in the female German cockroach

Virgin German cockroach adult females release an attractant that can be extracted with organic solvents and trapped from air blown over sexually receptive females. Behavioral assays with an olfactometer showed that the attractant was produced exclusively by adult females and it elicited behavioral responses in adult males, confirming its function as a female sex pheromone. Using behavioral and electrophysiological assays, we localized the site of pheromone production on the tenth abdominal tergite where an adult female-specific gland is found. Females whose glands were ablated were significantly less attractive to males than sham-operated control females.     

Rhythmicity of aminotransferase in the cockroach,Periplaneta americana

Summary Aspartate (AAT) and alanine aminotransferase (AIAT) activities in nervous system and coxal leg muscle of the cockroach showed circadian variations with maximal activity around midnight, alternating with minimal activity at 12.00 noon of the solar day. The enhanced activity levels of the enzymes observed during night dark hours may be related to higher energy requirements during increased locomotor activity of the animals.We thank Prof. K. S. Swami, for providing facilities. The financial help rendered by UGC and CSIR, in the form of Junior (to SV) and Senior (to TPK) Research Fellowships is acknowledged.     

Escape behavior in the cockroach: distributed neural processing

Escape reactions are often considered to be among the simplest behaviors. The nerve circuits guiding these reactions are also generally thought to be simple. For instance, in several species a single interneuron is sufficient to trigger normal escape. The evasive response of the cockroach, however, appears to be more complex both behaviorally and physiologically. In this review, several complications of the behavior are pointed out, based on a recent computer-graphic analysis of the leg movements. Next described is the cooperative role of several interneurons--not just one--in evoking an escape turn away from the stimulus. A model of this multicellular code for stimulus direction is then presented that correctly predicts the turning behavior under many different experimental conditions. Finally, an overall scheme of the information processing for escape behavior is presented.     

Escape behavior in the cockroach: Distributed neural processing

Summary Escape reactions are often considered to be among the simplest behaviors. The nerve circuits guiding these reactions are also generally thought to be simple. For instance, in several species a single interneuron is sufficient to trigger normal escape. The evasive response of the cockroach, however, appears to be more complex both behaviorally and physiologically. In this review, several complications of the behavior are pointed out, based on a recent computer-graphic analysis of the leg movements. Next described is the cooperative role of several interneurons-not just one-in evoking an escape turn away from the stimulus. A model of this multicellular code for stimulus direction is then presented that correctly predicts the turning behavior under many different experimental conditions. Finally, an overall scheme of the information processing for escape behavior is presented.     

Juvenile hormone titre and regulation in the cockroach Diploptera punctata

Titres of juvenile hormone (JH) have been determined in both hemolymph and whole body extracts of female Diploptera punctata during the first gonotrophic cycle using a method employing gas chromatography/mass spectrometry for qualitative and quantitative analysis. JH III is the sole JH found in both adult and last instar D. punctata. Maximum values of approximately 1500 ng/ml (approximately 6 microM) were observed at the middle of the gonotrophic cycle, when basal oocyte growth rate was greatest. Changes in rates of JH release in vitro by corpora allata paralleled closely the changes in JH titre, suggesting that biosynthesis is a major regulator of titre. JH levels per animal were calculated from observed JH titres, and at certain time points in the gonotrophic cycle JH obtained from analysis of whole bodies were significantly greater than those predicted from hemolymph titres. These results suggest the existence of a nonhemolymph JH pool in D. punctata. Decay in JH titre after allatectomy of 5 day females has also been studied. Following a rapid initial decline, the rate of decay slowed appreciably 4 h post-operation. Thus, use of a first-order rate constant to estimate half-life of JH significantly underestimated the longevity of the hormone. The apparent persistence of JH following allatectomy may be due to the existence of a nonhemolymph JH pool.     

An efferent respiratory modulation demonstrated in the olfactory bulb of the rat

The multiunit activity from mitral cells in the Rat olfactory bulb is modulated according to the respiratory cycle. Respiration and neuronal activity still coincide in tracheotomized animals, provided the olfactory peduncle is left intact.     

Autoradiographic studies of efferent nerves from the celiac ganglion in the cat

Summary Postganglionic sympathetic fibers originating in the celiac ganglion can be traced by autoradiography to the stomach, spleen, liver and pancreas.     

Spontaneous thermoregulatory oscillations in cutaneous efferent sympathetic activity

Summary Patterns of changes in cutaneous efferent sympathetic activity which have previously been shown to occur during experimental manipulation of the temperature of various thermosensitive body sites, have now been shown to accompany spontaneous thermoregulatory activity. That is, under thermoneural conditions, concurrent spontaneous oscillations in skin blood flow and efferent sympathetic activity were observed.     

A novel effect of cobalt treatment on calcium-dependent responses of the cockroach salivary gland

Summary After incubation in calcium-free solutions containing cobalt, the readmission of calcium caused prolonged but reversible hyperpolarization of acinar cells of cockroach salivary glands and prolonged fluid secretion. It is suggested that cobalt treatment increases the permeability of the acinar cell membrane to calcium.Acknowledgments. We are indebted to the Medical Research Council for support.     

Synaptic bar in the efferent part of a synapse in the organ of CORTI

Zusammenfassung Synapsenstäbchen (synaptic bars) wurden bisher im präsynaptischen Abschnitt afferenter Synapsen in Sinnesorganen beschrieben. Überrachenderweise fanden wir im Cortischen Organ eines Meerschweinchenfeten einen «synaptic bar» in einer efferenten Synapse, und zwar im basalen Cytoplasma einer äusseren Haarzellen senkrecht zur synaptischen Membran stehend und von Vesikeln (Durchmesser 33 nm) ungeben.     

Serotonin metabolism in the CNS in cerebellar ataxic mice

The metabolism of 5-hydroxytryptamine (5-HT) in the CNS was investigated in four kinds of morphologically different ataxic mice; reeler, staggerer, weaver and Purkinje cell degeneration mutants, and in hypocerebellar mice experimentally produced by injection of cytosine arabinoside. 5-HT and 5-hydroxyidoleacetic acid concentrations and tryptophan hydroxylase (TrpOH) activity were measured in the cerebrum, cerebellum and brain stem, respectively. TrpOH activity was significantly reduced only in the reeler mouse. The enhancements of the cerebellar 5-HT metabolism observed in the ataxic mice other than the reeler were supposed to be pseudo-enhancements subsequent to the cerebellar hypoplasia.     

Toxic effects of boric acid on the German cockroach

Boric acid is a slow-acting, inorganic insecticide whose mode of action has not been satisfactorily elucidated. Reported here is evidence which shows that ingested boric acid destroys the cellular lining of the foregut of German cockroaches,Blattella germanica (L.). This effect appears to be sufficient to bring about the death of the insects, perhaps ultimately by starvation. This finding is important because resistance to conventional insectivides may re-establish boric acid as a prominent cockroach control chemical.     

Absorption and excretion of benzpyrene in the cockroach (Periplaneta americana)

Résumé Le benzopyrène le pyrène et l'anthracène peuvent être révélés au moyen du spectrophotomètre dans les extraits de tissu des blattes (Periplaneta americana) nourries avec ces hydrocarbures; ils sont excrétés lorsqu'on interrompt l'alimentation.

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Supported by grant CA 01469-11 from the National Cancer Institute, Public Health Service.     

The adrenergic innervation of the efferent arterioles and the vasa recta in the mammalian kidney

Résumé En employant des techniques histochimiques nous avons étudié l'innervation adrénergique du rein des mammifères et démontré que les fibres adrénergiques entourent les artérioles et la partie supérieure des faisceaux des vasa recta.     

A metabolic pathway of gramine in barley

Résumé Nous avons observé que quand la gramine marqué au carbone attaché au noyau hétérocyclique a été administrée à des pousses d'orge agées de 60 jours (dans l'obscurité), 10% de la radioactivité a passé au CO₂ expiré et 0.4% au tryptophane.

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This investigation was supported by a grant from the University Medical Research Fund for which one of us (G.A.D.) is grateful. We are grateful to Dr.C. I. Abou-Chaar for useful discussions.