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Author (up) Anderson, J.L.; Albergotti, L.; Ellebracht, B.; Huey, R.B.; Phillips, P.C. file  url
  Title Does thermoregulatory behavior maximize reproductive fitness of natural isolates of Caenorhabditis elegans? Type Journal Article
  Year 2011 Publication BMC Evolutionary Biology Abbreviated Journal BMC Evol Biol  
  Volume 11 Issue Pages 157  
  Keywords Acclimatization; Animals; Body Temperature Regulation; Caenorhabditis elegans--genetics, physiology; Genetic Fitness; Temperature  
  Abstract BACKGROUND: A central premise of physiological ecology is that an animal's preferred body temperature should correspond closely with the temperature maximizing performance and Darwinian fitness. Testing this co-adaptational hypothesis has been problematic for several reasons. First, reproductive fitness is the appropriate measure, but is difficult to measure in most animals. Second, no single fitness measure applies to all demographic situations, complicating interpretations. Here we test the co-adaptation hypothesis by studying an organism (Caenorhabditis elegans) in which both fitness and thermal preference can be reliably measured. RESULTS: We find that natural isolates of C. elegans display a range of mean thermal preferences and also vary in their thermal sensitivities for fitness. Hot-seeking isolates CB4854 and CB4857 prefer temperatures that favor population growth rate (r), whereas the cold-seeking isolate CB4856 prefers temperatures that favor Lifetime Reproductive Success (LRS). CONCLUSIONS: Correlations between fitness and thermal preference in natural isolates of C. elegans are driven primarily by isolate-specific differences in thermal preference. If these differences are the result of natural selection, then this suggests that the appropriate measure of fitness for use in evolutionary ecology studies might differ even within species, depending on the unique ecological and evolutionary history of each population.  
  Call Number Serial 261  
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Author (up) Anderson, J.L.; Albergotti, L.; Proulx, S.; Peden, C.; Huey, R.B.; Phillips, P.C. file  url
  Title Thermal preference of Caenorhabditis elegans: a null model and empirical tests Type Journal Article
  Year 2007 Publication The Journal of Experimental Biology Abbreviated Journal J Exp Biol  
  Volume 210 Issue Pt 17 Pages 3107-3116  
  Keywords Acclimatization; Animals; Behavior, Animal; Body Temperature Regulation; Caenorhabditis elegans--physiology; Escherichia coli--growth & development; Models, Biological; Temperature  
  Abstract The preferred body temperature of ectotherms is typically inferred from the observed distribution of body temperatures in a laboratory thermal gradient. For very small organisms, however, that observed distribution might misrepresent true thermal preferences. Tiny ectotherms have limited thermal inertia, and so their body temperature and speed of movement will vary with their position along the gradient. In order to separate the direct effects of body temperature on movement from actual preference behaviour on a thermal gradient, we generate a null model (i.e. of non-thermoregulating individuals) of the spatial distribution of ectotherms on a thermal gradient and test the model using parameter values estimated from the movement of nematodes (Caenorhabditis elegans) at fixed temperatures and on a thermal gradient. We show that the standard lab strain N2, which is widely used in thermal gradient studies, avoids high temperature but otherwise does not exhibit a clear thermal preference, whereas the Hawaiian natural isolate CB4856 shows a clear preference for cool temperatures ( approximately 17 degrees C). These differences are not influenced substantially by changes in the starting position of worms in the gradient, the natal temperature of individuals or the presence and physiological state of bacterial food. These results demonstrate the value of an explicit null model of thermal effects and highlight problems in the standard model of C. elegans thermotaxis, showing the value of using natural isolates for tests of complex natural behaviours.  
  Call Number Serial 260  
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Author (up) Biron, D.; Shibuya, M.; Gabel, C.; Wasserman, S.M.; Clark, D.A.; Brown, A.; Sengupta, P.; Samuel, A.D.T. file  url
  Title A diacylglycerol kinase modulates long-term thermotactic behavioral plasticity in C. elegans Type Journal Article
  Year 2006 Publication Nature Neuroscience Abbreviated Journal Nat Neurosci  
  Volume 9 Issue 12 Pages 1499-1505  
  Keywords Animals; Association Learning/physiology; Behavior, Animal/*physiology; Body Temperature Regulation/physiology; Caenorhabditis elegans/*enzymology/genetics; Caenorhabditis elegans Proteins/genetics/*metabolism; Diacylglycerol Kinase/genetics/*metabolism; Gene Expression Profiling; Mutation; Neurons/enzymology; Thermosensing/*physiology  
  Abstract A memory of prior thermal experience governs Caenorhabditis elegans thermotactic behavior. On a spatial thermal gradient, C. elegans tracks isotherms near a remembered temperature we call the thermotactic set-point (T(S)). The T(S) corresponds to the previous cultivation temperature and can be reset by sustained exposure to a new temperature. The mechanisms underlying this behavioral plasticity are unknown, partly because sensory and experience-dependent components of thermotactic behavior have been difficult to separate. Using newly developed quantitative behavioral analyses, we demonstrate that the T(S) represents a weighted average of a worm's temperature history. We identify the DGK-3 diacylglycerol kinase as a thermal memory molecule that regulates the rate of T(S) resetting by modulating the temperature range of synaptic output, but not temperature sensitivity, of the AFD thermosensory neurons. These results provide the first mechanistic insight into the basis of experience-dependent plasticity in this complex behavior.  
  Call Number Serial 1679  
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Author (up) Guilloux, J.-P.; David, D.J.P.; Xia, L.; Nguyen, H.T.; Rainer, Q.; Guiard, B.P.; Reperant, C.; Deltheil, T.; Toth, M.; Hen, R.; Gardier, A.M. file  url
doi  openurl
  Title Characterization of 5-HT(1A/1B)-/- mice: an animal model sensitive to anxiolytic treatments Type Journal Article
  Year 2011 Publication Neuropharmacology Abbreviated Journal Neuropharmacology  
  Volume 61 Issue 3 Pages 478-488  
  Keywords Animals; Anti-Anxiety Agents/*therapeutic use; Anxiety/*drug therapy/metabolism/physiopathology; Behavior, Animal/drug effects; Body Temperature Regulation; *Disease Models, Animal; Frontal Lobe/drug effects/metabolism; Gene Expression; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurons/drug effects/metabolism; Paroxetine/therapeutic use; RNA, Messenger/metabolism; Raphe Nuclei/drug effects/metabolism; Receptor, Serotonin, 5-HT1A/genetics/*physiology; Receptor, Serotonin, 5-HT1B/genetics/*physiology; Serotonin/metabolism; Serotonin Plasma Membrane Transport Proteins/genetics/metabolism; Serotonin Uptake Inhibitors/therapeutic use; Synaptic Transmission/drug effects  
  Abstract Selective serotonin (5-HT) re-uptake inhibitors (SSRIs) are commonly used in the treatment of generalized anxiety disorder in Humans. However, because only few animal models display overt anxious-like behavior, detailed preclinical studies of the anxiolytic properties of antidepressants are still lacking. Here, we studied the neurochemical and behavioral effects of a double 5-HT(1A/1B) receptor knockout in mice (5-HT(1A/1B)-/-) as compared to their wild-type littermates (5-HT(1A/1B)+/+). It is known that single deletion of either 5-HT(1A) or 5-HT(1B) receptor induces behavioral changes that are not correlated with differences in brain serotonergic tone. Deletion of both receptors resulted in (i) higher emotionality of animals, as observed in three unconditioned paradigms of anxiety (open field, elevated plus maze and novelty suppressed feeding tests); (ii) a approximately 200% increase in the mean spontaneous firing rate of 5-HT neurons in the dorsal raphe nucleus (DRN) compared to 5-HT(1A/1B)+/+ mice; (iii) elevated basal dialysate levels of 5-HT in the DRN and frontal cortex; (iv) an exaggerated response to acute paroxetine administration in microdialysis experiments, and (v) increased basal core body temperature. These findings suggest that the deletion of both autoreceptors induces a strong anxious-like behavioral state associated with increased 5-HT neurotransmission. Interestingly, 5-HT(1A/1B)-/- mice are still sensitive to the acute administration of diazepam. Moreover, while deletion of both receptors impacted on the response to acute SSRI treatment in the forced swim test, anxiolytic-like effects of a chronic SSRI treatment were still observed in 5-HT(1A/1B)-/- mice. Thus, the 5-HT(1A/1B)-/- mouse model could be of great interest to unveil the mechanisms of action of the anxiolytic effects of SSRIs.  
  Call Number ] Serial 173  
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Author (up) Ho, L.T.; Lin, M.T. file  url
  Title A dopamine-acetylcholine link in the caudate-putamen complex which mediates metabolic rate Type Journal Article
  Year 1982 Publication Metabolism: Clinical and Experimental Abbreviated Journal Metabolism  
  Volume 31 Issue 8 Pages 791-796  
  Keywords Acetylcholine/*pharmacology; Animals; Apomorphine/pharmacology; Atropine/pharmacology; *Body Temperature Regulation/drug effects; Caudate Nucleus/*physiology; Dopamine/*physiology; Dose-Response Relationship, Drug; Haloperidol/pharmacology; Male; Oxygen Consumption/drug effects; Putamen/*physiology; Rats; Vasoconstriction/drug effects  
  Abstract In order to investigate the possible involvement of the dopaminergic and the cholinergic neurons of caudate-putamen complex (CP) in temperature regulation, we have assessed the effects of administration of either acetylcholine (Ach), atropine (Ach receptor antagonist), apomorphine (DA receptor agonist), or haloperidol (DA receptor antagonist) into the CP on metabolic, respiratory, vasomotor and temperature responses in conscious rats at various ambient temperature (Ta). The results show that intra-CP injection of either Ach or apomorphine caused hypothermia, decreased metabolism and cutaneous vasoconstriction at Ta 8 and 22 degrees C, as well as hyperthermia and cutaneous vasoconstriction at Ta 30 degrees C. On the other hand, intra-Cp injection of either atropine or haloperidol caused hyperthermia, increased metabolism and cutaneous vasoconstriction at all Ta (8, 22, and 30 degrees C) studied. There was no change in respiratory evaporative heat loss in response to these agents at all Ta studied. Furthermore, the Ach-induced hypothermia or hypo-metabolism was antagonized by pretreatment with atropine, but not with haloperidol. However, the apomorphine-induced hypothermia or hypo-metabolism at Ta 8 and 22 degrees C was antagonized by pretreatment with either atropine or haloperidol. These observations tend to indicate that a dopamine-acetylcholine link occurs in the caudate-putamen complex which mediate metabolic rate in the rat.  
  Call Number Serial 1527  
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