Chemical communication in invertebrates

Conclusions In conclusion, olfactory pheromones are widespread in nature and control many fundamental aspects of an insect's life. Detailed behavioral observations in the field and laboratory indicate the great complexity of most pheromone communication systems. The preliminary electrophysiological experiments on single olfactory receptor neurons that we have described here, point toward the possibility of unraveling the basic physiological mechanisms underlying these behavioral complexities. This information is directly applicable to many problem areas in chemoreception and could provide a base for the rational use of pheromones in the control of insect pests. *** DIRECT SUPPORT *** A2025171 00003     

Intrinsic and extrinsic neural and neurohumoral control of the decapod heart

The intra-cardiac nervous system of the decapod heart is composed of large and small ganglionic cells (LGCs and SGCs) and axons of extrinsic cardio-acceleratory and-inhibitory neurons (CAs and CIs). Candidate neurotransmitters for the neurons have been determined by pharmacological, cytochemical and immunocytochemical tests. SGCs may be cholinergic, LGCs and CAs are probably dopaminergic, and CIs are GABAergic. Serotonin and octopamine were cardio-excitatory neuromodulators of the heart. Proctolin, crustacean cardio-active peptide (CCAP), red pigment concentrating hormone (RPCH), and FMRFamide also had modulatory actions on the heart. Proctolin was the most potent peptide, which acted primary on the cardiac ganglion. Insect adipokinetic hormones had little effect on the heart.     

Nonspecific esterase activity in monkey thymus lymphocytes; study of distribution in lymphocyte subpopulation

Summary A subpopulation of monkey thymus lymphocytes was investigated by direct nonspecific esterase staining of Erosette forming lymphocytes. Thymus lymphocytes had high nonspecific esterase activity and E-rosette formation, but the level of their in vitro lectin responses was very low. *** DIRECT SUPPORT *** A2025117 00012     

Heterotrophic growth in the blue-green algaAnacystis nidulans

Summary Anacystis nidulans was grown heterotrophically in the dark for the first time. Pyruvate served as the carbon source. The cells did not make pigments when grown heterotrophically, but synthesis of pigments resumed upon transfer of the cells to the light. *** DIRECT SUPPORT *** A2025089 00005     

Locomotor behavior in relation to octopamine levels in the antLasius niger

Summary The heads and bodies of hyperactive and hypoactive ants, selected on the basis of motor activity, were tested for their octopamine content. The level was found to be significantly higher in hyperactive animals. A possible involvement of octopamine in locomotor behavior is discussed.     

Octopamine,dopamine and noradrenaline content of the brain of the locust,Schistocerca gregaria

Summary The octopamine, dopamine and noradrenaline content of the brain of the locust,Schistocerca gregaria has been determined using sensitive radiochemical-enzymatic assays. Octopamine and dopamine are present in high concentration but the noradrenaline content is only 1/25 that of octopamine. Both reserpine and fusaric acid (a dopamine--hydroxylase inhibitor) produce a significant depletion of the octopamine stores.The author is a M.R.C. of Canada Fellow. Thanks are due to Drs.A. A. Boulton, A. V. Juorio, andP. H. Wu for helpful discussion.     

Erythrocyte membrane lipid peroxidation in iron deficiency anemia

Summary Erythrocytes from normal subjects and from cases of iron deficiency anemia were exposed to hydrogen peroxide and the extent of membrane lipid peroxidation studied. Significantly less peroxidation was observed in intact anemic erythrocytes compared to normal. However, when isolated membrane lipids were subjected to peroxidation, there was no significant difference between the two groups. It is unlikely that lipid peroxidation per se plays a major role in the reported decrease in red cell life-span in iron deficiency. *** DIRECT SUPPORT *** A2025146 00003     

Alpha-fetoprotein in tumor-bearing mice assayed by particle agglutination inhibition

Summary Serum alpha-fetoprotein (AFP) in hepatoma BW7756-bearing mice was measured by a new particle agglutination inhibition test employing AFP adsorbed to charcoal particles. The AFP levels and tumor weights showed nearly parallel increases to means of 2633 g/ml and 5.2 g, respectively, 28 days after implantation. *** DIRECT SUPPORT *** A2025089 00011     

Neuromodulation by serotonin and octopamine in the honeybee: behaviour,neuroanatomy and electrophysiology

The biogenic amines serotonin (5HT) and octopamine (OA) exist in the bee and can modulate neuronal activity and behaviour. 5HT-like and OA-like immunoreactivities can be found in most neuropils of the brain. Binding sites for the two amines are also present in most brain neuropils. The highest density of binding sites for [³H]serotonin and [³H]octopamine was found in the mushroom bodies. In some brain areas, especially the mushroom bodies, mismatches exist between binding sites and immunoreactivities, suggesting that the two amines also bind to neuropils which are not directly innervated by 5HT-like or OA-like immunoreactive neurons. The action of the two amines on behaviour in the bee is antagonistic. In the antennal pathway, proboscis and antennal responses to olfactory and gustatory stimuli are enhanced by OA and reduced by 5HT. In olfactory conditioning experiments, storage and retrieval of the learned signal can be enhanced by OA and reduced by 5HT. The specificity of these effects depends on the site of amine application in the neuropil. In the visual system the direction specificity of the visual antennal response is enhanced by OA and reduced by 5HT after topical application or injection into the lobula, the third optic ganglion. Correlates for the behavioural modulation can be found in higher-order visual interneurons. While OA application can mimic the stimulation of the bee with sugar water, the behavioural conditions leading to the release of 5HT are not yet known.     

Octopamine levels during the moult cycle and adult development in the migratory locust, Locusta migratoria.

Octopamine content of the head of the locust Locusta migratoria has been determined during the last larval stage, moulting and adult life of 3 groups of insects: female and male gregarious, solitary and CO2 solitarized. An important difference was found between these 3 groups. Octopamine contents increased in the middle of the larval life and during the adult life. The moulting time is characterized by a sharp decrease of the octopamine content which becomes identical in the 3 groups of insects. The relation between octopamine content, hormone cycles and motility is discussed.     

Cholecystokinin-like peptides in avian brain and gut

Summary Extracts of turkey brain and jejunum contain a factor closely resembling the COOH-terminal octapeptide of porcine cholecystokinin (CCK). Turkey antral extracts contain factors distinguishable in immunochemical and gel filtration properties from the mammalian forms of gastrin and CCK. *** DIRECT SUPPORT *** A2025089 00007Acknowledgments. Skilled technical assistance was given by Elaine Clarke, Carol Higgins and Gavin Laing. Pure natural human G17 and G34 were generously provided by Prof. R.A. Gregory and Dr H.J. Tracy; pure natural porcine CCK33 was a generous gift from Prof. Viktor Mutt; the Squibb Institute for Medical Research kindly provided supplies of synthetic CCK8, and synthetic caerulein was a gift from Farmitalia Ltd.     

Dopamine and octopamine in whole body extracts of the bulb mite

Summary Using high performance liquid chromatography with electrochemical detection, whole body extracts of the bulb mite,Rhizoglyphus echinopus (Fumouze and Robin), were found to contain the biogenic amines dopamine and octopamine at concentrations of 4.3±0.6 and 2.3±1.4 ng g^–1 wet weight, respectively. Adrenaline, noradrenaline, tyramine,N-methyldopamine,N-acetyldopamine, and 5-hydroxytryptamine, if present, were below the limits of detectability. This is the initial demonstration of the presence of octopamine in a mite species.     

Octopamine levels during the moult cycle and adult development in the migratory locust,Locusta migratoria

Summary Octopamine content of the head of the locustLocusta migratoria has been determined during the last larval stage, moulting and adult life of 3 groups of insects: female and male gregarious, solitary and CO₂ solitarized. An important difference was found between these 3 groups. Octopamine contents increased in the middle of the larval life and during the adult life. The moulting time is characterized by a sharp decrease of the octopamine content which becomes identical in the 3 groups of insects. The relation between octopamine content, hormone cycles and motility is discussed.     

Are there cyclic variations in estradiol secretion in the non-pregnant rabbit?

Summary Plasma estradiol-17 (E2) concentration was measured in 5 adult non-pregnant rabbits each in 3 different seasons (January, April and September). Blood samples were taken from each rabbit every other day. There was a considerable variation in plasma E2 levels from one sampling day to another, irrespective of the season. The pattern of variation in E2 levels in individual rabbits tended to be cyclic and this cycle was roughly of the order of 8 days. There was no correlation between changes in E2 levels and those in the vaginal appearance. *** DIRECT SUPPORT *** A2025089 00013This study was supported by the Ford Foundation, and the Swedish Medical Research Council (project No. 4781).     

Failure of somatostatin to influence experimental tumor cell growth in vivo and in vitro

Summary The influence of somatostatin on tumor cell growth was studied in vivo in mice (sarcoma 180 ascites tumor and Lewis lung tumor) and in vitro on nontransformed and polyoma-transformed cell lines. 4 or 20 g/100 g of cyclic somatostatin and 4 g/100 g of linear protamin Zn-bound somatostatin were injected s.c. twice daily in the in vivo study. Cyclic somatostatin (1, 4 or 10 g/ml) was added twice daily to the cell cultures. Somatostatin administration influenced neither the survival of animals nor the growth rate of cultured cell lines. *** DIRECT SUPPORT *** A2025117 00011     

Octopaminergic control of corpora allata activity in an insect

Summary Octopamine enhanced the release of JH3 from isolated corpora allata of locusts in short-term cultures. This effect was suppressed when phentolamine (inhibitor of the octopamine receptors) was added to the culture medium. Moreover an octopamine-sensitive adenylate cyclase was found in the corpora allata. The results suggest a positive octopaminergic control on the activity of the corpora allata.     

In vitro biosynthesis of octopamine by the nervous system and the heart of the mollusc gastropode Helix pomatia (author's transl)]

The tyrosine is decarboxylated in vitro by the central nervous tissue and by the intracardiac nervous tissue of Helix pomatia by aromatic amino-acid decarboxylase. The tyramine obtained is then partially transformed into octopamine by tyramine-beta-hydroxylase. The inhibition of monoamine oxidase favours apparition of the 2 amines. The monoamine oxidase seems able to regulate their synthese and to assure their inactivation.     

Biogenic amine acetylation: No detectable circadian rhythm in whole brain homogenates of the insectOstrinia nubilalis

Summary With the biogenic amines tryptamine, dopamine, and octopamine as substrates, N-acetyltransferase activity shows no detectable circadian rhythm in homogenates of whole brains of the European corn borerOstrinia nubilalis (Lepidoptera: Pyralidae). The circadian clock of this insect may be fundamentally different from the N-acetyltransferase pacemaker in the pineal gland of vertebrates.     

Effect of cyproheptadine on the octopamine-induced responses in the mammalian central nervous system

Summary Extracellular recordings have been made from rat thalamic neurones anaesthetized with urethane, 1.5–2 g/kg i.p. Iontophoretically applied octopamine excited certain thalamic neurones in the ventral basal complex while inhibiting others. Both effects were reversibly antagonized by iontophoretically applied cyproheptadine without affecting responses to noradrenaline and dopamine.Acknowledgment. We are grateful to Merck, Sharp and Dohme for a gift of cyproheptadine HCl.     

Neural correlates of oder-guided behaviors

Concluding remarks From the above considerations, it appears that the structural organization of the central nervous system, as defined by the anatomy, is not necessarily superposed on the one operating from the neurophysiological point of view, especially in the behaving model. The nested functional units have to be defined in terms of their spatial and temporal dimensions, and to be studied on an accurate scale which might call for complementary methods. As long as these basic principles are maintained, neuro-behavioral correlates can be observed in various organizational levels of the olfactory system. Moreover, it is possible to understand events at one spatio-temporal degree from what is known about the next degree on the scale. Simply, the events will be observed with some undeterminism, if the recording and analyzing methods are not adjusted accordingly, whenever the resolution of the study is reduced. This character is shared with experimental models in any other field of the sciences.The consistency of simultaneous neuronal and behavioral events merely illustrates the projection of the same reality onto the parallel planes of physiology and psychology. Finally, one could object that trying to construct bridges between the two phenomenologic levels is reductionism, in one direction, and irrationalism, in the other. In the present state of the art, it seems at least reasonable to predict that the neurophysiology of unpredictable events would progress further, due to the construction of intermediate arcs between the most extreme levels of organization in the behaving subject. *** DIRECT SUPPORT *** A2025171 00004