Associative learning drives longitudinally-graded presynaptic plasticity of neurotransmitter release along axonal compartments

Anatomical and physiological compartmentalization of neurons is a mechanism to increase the computational capacity of a circuit, and a major question is what role axonal compartmentalization plays. Axonal compartmentalization may enable localized, presynaptic plasticity to alter neuronal output in a flexible, experience-dependent manner. Here we show that olfactory learning generates compartmentalized, bidirectional plasticity of acetylcholine release that varies across the longitudinal compartments of Drosophila mushroom body (MB) axons. The directionality of the learning-induced plasticity depends on the valence of the learning event (aversive vs. appetitive), varies linearly across proximal to distal compartments following appetitive conditioning, and correlates with learning-induced changes in downstream mushroom body output neurons (MBONs) that modulate behavioral action selection. Potentiation of acetylcholine release was dependent on the CaV2.1 calcium channel subunit cacophony. In addition, contrast between the positive conditioned stimulus and other odors required the inositol triphosphate receptor (IP3R), which was required to maintain responsivity to odors in untrained conditions. Downstream from the mushroom body, a set of MBONs that receive their input from the γ3 MB compartment were required for normal appetitive learning, suggesting that they represent a key node through which discriminative effects influence appetitive memory and decision-making. These data demonstrate that learning drives valence correlated, compartmentalized, bidirectional potentiation and depression of synaptic neurotransmitter release, which rely on distinct mechanisms and are distributed across axonal compartments in a learning circuit.

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Predictive olfactory learning in Drosophila

Scientific Reports ◽

10.1038/s41598-021-85841-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chang Zhao ◽

Yves F. Widmer ◽

Sören Diegelmann ◽

Mihai A. Petrovici ◽

Simon G. Sprecher ◽

...

Keyword(s):

Synaptic Plasticity ◽

Dopaminergic Neurons ◽

Mushroom Body ◽

Trace Conditioning ◽

Fruit Fly ◽

Olfactory Learning ◽

Shock Strength ◽

Behavioral Experiments ◽

Kenyon Cells ◽

Output Neurons

AbstractOlfactory learning and conditioning in the fruit fly is typically modelled by correlation-based associative synaptic plasticity. It was shown that the conditioning of an odor-evoked response by a shock depends on the connections from Kenyon cells (KC) to mushroom body output neurons (MBONs). Although on the behavioral level conditioning is recognized to be predictive, it remains unclear how MBONs form predictions of aversive or appetitive values (valences) of odors on the circuit level. We present behavioral experiments that are not well explained by associative plasticity between conditioned and unconditioned stimuli, and we suggest two alternative models for how predictions can be formed. In error-driven predictive plasticity, dopaminergic neurons (DANs) represent the error between the predictive odor value and the shock strength. In target-driven predictive plasticity, the DANs represent the target for the predictive MBON activity. Predictive plasticity in KC-to-MBON synapses can also explain trace-conditioning, the valence-dependent sign switch in plasticity, and the observed novelty-familiarity representation. The model offers a framework to dissect MBON circuits and interpret DAN activity during olfactory learning.

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246 Examining Melatonin-induced Changes in Uterine Blood Flow and Vaginal Temperatures in Nutrient Restricted Pregnant Heifers

Journal of Animal Science ◽

10.1093/jas/skab235.241 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 132-132

Author(s):

Zully E Contreras-Correa ◽

Riley D Messman ◽

Hector Sanchez-Rodriguez ◽

Caleb O Lemley

Keyword(s):

Blood Flow ◽

Repeated Measures ◽

Farm Animals ◽

Nutrient Restriction ◽

Dependent Manner ◽

Uterine Blood Flow ◽

Time Interaction ◽

Main Effect ◽

Treatment Interaction ◽

Induced Changes

Abstract The objectives were to examine melatonin mediated changes in temporal uterine blood flow (UBF) and vaginal temperatures (VT) in 54 Brangus heifers (Fall, n = 29; Summer, n = 25) during compromised pregnancy. At d160 of gestation, heifers were assigned to 1 of 4 groups consisting of adequately fed (ADQ-CON; 100% NRC; n=13), global nutrient restricted (RES-CON; 60% NRC; n = 13), and ADQ or RES supplemented with 20 mg of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). In the morning (0500h) and afternoon (1300h) of d220 of gestation, temperature dataloggers (Onset Computer Corporation) attached to progesterone-free CIDRs were used to record VT, while UBF was determined via Doppler ultrasonography. Data were analyzed using repeated measures of ANOVA (SAS). Significant differences were found in UBF and VT between Fall and Summer groups (P< 0.05), therefore seasons were individually analyzed. In Fall, a nutrition by treatment interaction was significant, where the RES-CON heifers exhibited reduced total UBF compared to ADQ-CON (5.67±0.68 vs. 7.97±0.54 L/min; P = 0.012). In Summer, there was not a main effect of nutrition (P = 0.390); nevertheless, the MEL heifers exhibited increased total UBF compared to the CON counterparts (8.16±0.73 vs. 6.00±0.70 L/min; P = 0.048). Moreover, there was a nutrition by treatment by time interaction in VT for Fall and Summer heifers (P < 0.0001). In Fall, all groups had decreased VT in the morning compared to the afternoon (P < 0.0001). Whereas, in Summer, VT increased for ADQ-CON, RES-CON, and ADQ-MEL from morning to afternoon (P < 0.0001), while the RES-MEL remained constant throughout the day (P = 0.649). Furthermore, during the afternoon RES-MEL heifers exhibited decreased VT compared to ADQ-CON (38.91±0.09 vs. 39.26±0.09°C, respectively; P=0.039). In summary, nutrient restriction and melatonin supplementation altered UBF in a season dependent manner. Additionally, with the VT differences observed in Summer, future studies should evaluate the potential of melatonin supplementation for mitigating heat stress in farm animals.

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Pancreatic polypeptide inhibits pancreatic enzyme secretion via a cholinergic pathway

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1987.253.5.g706 ◽

1987 ◽

Vol 253 (5) ◽

pp. G706-G710 ◽

Cited By ~ 3

Author(s):

G. Jung ◽

D. S. Louie ◽

C. Owyang

Keyword(s):

Pancreatic Polypeptide ◽

Acetylcholine Release ◽

Pancreatic Enzyme ◽

Enzyme Secretion ◽

Dependent Manner ◽

Amylase Release ◽

Opioid Receptor Antagonists ◽

Cholinergic Pathway ◽

Pancreatic Enzyme Secretion ◽

Dose Dependent

In rat pancreatic slices, rat pancreatic polypeptide (PP) or C-terminal hexapeptide of PP [PP-(31-36)] inhibited potassium-stimulated amylase release in a dose-dependent manner. The inhibition was unaffected by addition of hexamethonium but blocked by atropine. In contrast, PP(31-36) did not have any effect on acetylcholine- or cholecystokinin octapeptide-stimulated amylase release. In addition, when pancreatic slices were incubated with [3H] choline, PP(31-36) inhibited the potassium-evoked release of synthesized [3H] acetylcholine in a dose-dependent manner. The inhibitory action of PP was unaffected by adrenergic, dopaminergic, or opioid receptor antagonists. Thus PP inhibits pancreatic enzyme secretion via presynaptic modulation of acetylcholine release. This newly identified pathway provides a novel mechanism for hormonal inhibition of pancreatic enzyme secretion via modulation of the classic neurotransmitter function.

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Selective dendritic localization of mRNA in Drosophila mushroom body output neurons

eLife ◽

10.7554/elife.62770 ◽

2021 ◽

Vol 10 ◽

Author(s):

Jessica Mitchell ◽

Carlas S Smith ◽

Josh Titlow ◽

Nils Otto ◽

Pieter van Velde ◽

...

Keyword(s):

Single Molecule ◽

Nicotinic Acetylcholine Receptors ◽

Neuronal Plasticity ◽

Mushroom Body ◽

Acetylcholine Receptors ◽

Behavioural Change ◽

Before And After ◽

Specific Mrnas ◽

Output Neurons ◽

Subcellular Resolution

Memory-relevant neuronal plasticity is believed to require local translation of new proteins at synapses. Understanding this process requires the visualization of the relevant mRNAs within these neuronal compartments. Here we used single-molecule fluorescence in situ hybridization (smFISH) to localize mRNAs at subcellular resolution in the adult Drosophila brain. mRNAs for subunits of nicotinic acetylcholine receptors and kinases could be detected within the dendrites of co-labelled Mushroom Body Output Neurons (MBONs) and their relative abundance showed cell-specificity. Moreover, aversive olfactory learning produced a transient increase in the level of CaMKII mRNA within the dendritic compartments of the 52a MBONs. Localization of specific mRNAs in MBONs before and after learning represents a critical step towards deciphering the role of dendritic translation in the neuronal plasticity underlying behavioural change in Drosophila.

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Lead induced changes in biomarkers and proteome map of Chicory (Cichorium intybus L.)

Current Botany ◽

10.25081/cb.2020.v11.6182 ◽

2020 ◽

pp. 111-116

Author(s):

Bisma Malik ◽

Tanveer Bilal Pirzadah

Keyword(s):

Contaminated Soils ◽

Research Work ◽

Biomass Accumulation ◽

Cichorium Intybus ◽

Dependent Manner ◽

Proteomics Data ◽

Concentration Dependent Manner ◽

Pb Stress ◽

Metal Treatment ◽

Induced Changes

Lead (Pb) toxicity is a serious environmental problem as it affects the food production by interfering plant growth and development, thus declines the production yield. In the present research work, Cichorium intybus L. plants were subjected to different concentrations of Pb (0, 100, 200 and 300µM) upto 46days to determine the oxidative stress. The length of root and shoot, accumulation of biomass were estimated along with the changes in biomarkers (H2O2 and TBARS). Further proteomic analysis of chicory leaves (46days old) at 300µM Pb concentration was done to identify the proteins of interest. The root growth increased significantly in a concentration-dependent manner however; shoot growth, biomass accumulation declined significantly with Pb stress compared to control. Changes in biomarkers (H2O2 and TBARS) content elevated with the increment in the concentration of metal treatment but exhibited a gradual decline at 300µM Pb treatment.. Proteomics data of 46days old chicory plants under 300 µM Pb stress analyzed by PDQuest software detected approximately 168 protein spots on each gel and 81 spots were differentially expressed in which 16 were up-regulated and 13 were down-regulated. The present study suggested that chicory possess a strong antioxidative defense system to combat Pb stress and thus could be explored for cultivation in Pb contaminated soils.

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Long-term memory requires sequential protein synthesis in three subsets of mushroom body output neurons in Drosophila

Scientific Reports ◽

10.1038/s41598-017-07600-2 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 13

Author(s):

Jie-Kai Wu ◽

Chu-Yi Tai ◽

Kuan-Lin Feng ◽

Shiu-Ling Chen ◽

Chun-Chao Chen ◽

...

Keyword(s):

Protein Synthesis ◽

Mushroom Body ◽

Long Term Memory ◽

Term Memory ◽

Output Neurons

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Multimodal integration and stimulus categorization in putative mushroom body output neurons of the honeybee

Royal Society Open Science ◽

10.1098/rsos.171785 ◽

2018 ◽

Vol 5 (2) ◽

pp. 171785 ◽

Cited By ~ 23

Author(s):

Martin F. Strube-Bloss ◽

Wolfgang Rössler

Keyword(s):

Visual Information ◽

Mushroom Body ◽

Visual Cues ◽

Sensory Modality ◽

Sensory Information ◽

Insect Brain ◽

Pollinating Insects ◽

Output Neurons ◽

Electrophysiological Characterization ◽

Nonlinear Integration

Flowers attract pollinating insects like honeybees by sophisticated compositions of olfactory and visual cues. Using honeybees as a model to study olfactory–visual integration at the neuronal level, we focused on mushroom body (MB) output neurons (MBON). From a neuronal circuit perspective, MBONs represent a prominent level of sensory-modality convergence in the insect brain. We established an experimental design allowing electrophysiological characterization of olfactory, visual, as well as olfactory–visual induced activation of individual MBONs. Despite the obvious convergence of olfactory and visual pathways in the MB, we found numerous unimodal MBONs. However, a substantial proportion of MBONs (32%) responded to both modalities and thus integrated olfactory–visual information across MB input layers. In these neurons, representation of the olfactory–visual compound was significantly increased compared with that of single components, suggesting an additive, but nonlinear integration. Population analyses of olfactory–visual MBONs revealed three categories: (i) olfactory, (ii) visual and (iii) olfactory–visual compound stimuli. Interestingly, no significant differentiation was apparent regarding different stimulus qualities within these categories. We conclude that encoding of stimulus quality within a modality is largely completed at the level of MB input, and information at the MB output is integrated across modalities to efficiently categorize sensory information for downstream behavioural decision processing.

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Somatostatin stimulates acetylcholine release in the canine heart

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1989.257.2.h483 ◽

1989 ◽

Vol 257 (2) ◽

pp. H483-H487

Author(s):

J. W. Wiley ◽

L. Uccioli ◽

C. Owyang ◽

T. Yamada

Keyword(s):

Acetylcholine Release ◽

Gel Filtration ◽

Negative Inotropic Effect ◽

Molecular Forms ◽

Dependent Manner ◽

Canine Heart ◽

Release Of Acetylcholine ◽

The Right ◽

A Minor ◽

Somatostatin 14

Previous reports of somatostatin's atropine-sensitive negative inotropic effect on cardiac function prompted the present studies to characterize the molecular forms and actions of somatostatin in the canine heart. Radioimmunoassay of cardiac extracts revealed concentrations of somatostatin-like immunoreactivity ranging from 0.50 +/- 0.13 pmol/g tissue (means +/- SE, n = 6) in the pulmonary artery to 0.78 +/- 0.23 pmol/g tissue in the right ventricle. On gel filtration of the extracts, two major molecular forms of somatostatin-like immunoreactivity were elicited, the predominant one coeluting with somatostatin-14 and a minor peak corresponding to somatostatin-28. Experiments performed with slices of atrial septum indicated that somatostatin-14 (10(-10) to 10(-7) M) stimulated the release of acetylcholine in a dose-dependent manner. This action of somatostatin-14 was additive with K+-evoked acetylcholine release, unaffected by hexamethonium, and blocked by tetrodotoxin, suggesting mediation via a nonnicotinic postganglionic neural pathway. Our studies lead us to conclude that somatostatin may function as a neurotransmitter in the heart, which exerts its negative inotropic action by promoting the release of acetylcholine.

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