Dendritic Release of Neurotransmitters

Ludwig, Mike; Apps, David K.; Menzies, John; Patel, Jyoti; Rice, Margaret E.

doi:10.1002/cphy.c160007

Cited by 54 publications

(60 citation statements)

References 273 publications

(430 reference statements)

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“…One such signal is oxytocin, and we have shown previously that gavage of SCM activates magnocellular oxytocin cells . Oxytocin can be released into the brain from central dendrites to act at distant sites, oxytocin‐immunoreactive nerve fibres are reported to enter the SuM and oxytocin binding sites are present in the rat SuM . In acute brain slice preparations, oxytocin receptor agonists activate approximately half of SuM cells tested .…”

Section: Discussionmentioning

confidence: 97%

Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration

May

Hume

Sabatier

et al. 2019

J Neuroendocrinology

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The circulating orexigenic hormone ghrelin targets many brain areas involved in feeding control and signals via a dedicated receptor, the growth hormone secretagogue receptor 1A. One unexplored target area for ghrelin is the supramammillary nucleus (SuM), a hypothalamic area involved in motivation and reinforcement and also recently linked to metabolic control. Given that ghrelin binds to the SuM, we explored whether SuM cells respond to ghrelin and/or are activated when endogenous ghrelin levels are elevated. We found that peripheral ghrelin injection activates SuM cells in rats, reflected by an increase in the number of cells expressing c‐Fos protein in this area, as welll as by the predominantly excitatory response of single SuM cells recorded in in vivo electrophysiological studies. Further c‐Fos mapping studies reveal that this area is also activated in rats in situations when circulating ghrelin levels are known to be elevated: in food‐restricted rats anticipating the consumption of food and in fed rats anticipating the consumption of an energy‐dense food. We also show that intra‐SuM injection of ghrelin induces a feeding response in rats suggesting that, if peripheral ghrelin is able to access the SuM, it may have direct effects on this brain region. Collectively, our data demonstrate that the SuM is activated when peripheral ghrelin levels are high, further supporting the emerging role for this brain area in metabolic and feeding control.

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Section: Discussionmentioning

confidence: 97%

Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration

May

Hume

Sabatier

et al. 2019

J Neuroendocrinology

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“…High spatiotemporal imaging of neuromodulatory signaling is essential to understand the dynamics of neuromodulator release and uptake in neural circuits and to elucidate the function of chemical neuromodulation in animal behavior (39). Synthetic probes are an attractive approach to imaging neuromodulators such as 5-HT owing to their photostability, compatibility with pharmacology, and feasibility for use in genetically intractable organisms.…”

Section: Discussionmentioning

confidence: 99%

High-throughput evolution of near-infrared serotonin nanosensors

et al. 2019

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Imaging neuromodulation with synthetic probes is an emerging technology for studying neurotransmission. However, most synthetic probes are developed through conjugation of fluorescent signal transducers to preexisting recognition moieties such as antibodies or receptors. We introduce a generic platform to evolve synthetic molecular recognition on the surface of near-infrared fluorescent single-wall carbon nanotube (SWCNT) signal transducers. We demonstrate evolution of molecular recognition toward neuromodulator serotonin generated from large libraries of ~6.9 × 1010 unique ssDNA sequences conjugated to SWCNTs. This probe is reversible and produces a ~200% fluorescence enhancement upon exposure to serotonin with a Kd = 6.3 μM, and shows selective responsivity over serotonin analogs, metabolites, and receptor-targeting drugs. Furthermore, this probe remains responsive and reversible upon repeat exposure to exogenous serotonin in the extracellular space of acute brain slices. Our results suggest that evolution of nanosensors could be generically implemented to develop other neuromodulator probes with synthetic molecular recognition.

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“…Transmitter release from neuronal dendrites does not depend on action potentials in the presynaptic neurons (Ludwig et al . ). The OB glomerular circuit is very rich in dendrodendritic synapses.…”

Section: Resultsmentioning

confidence: 97%

Cholecystokinin selectively activates short axon cells to enhance inhibition of olfactory bulb output neurons

Liu

2018

The Journal of Physiology

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Neuropeptides such as cholecystokinin (CCK) are important for many brain functions, including sensory processing. CCK is predominantly present in a subpopulation of excitatory neurons and activation of CCK receptors is implicated in olfactory signal processing in the olfactory bulb (OB). However, the cellular and circuit mechanisms underlying the actions of CCK in the OB remain elusive. In the present study, we characterized the effects of CCK on synaptic inhibition of the principal OB output neurons mitral/tufted cells (MTCs) followed by mechanistic analyses at both circuit and cellular levels. First, we found that CCK via CCK-B receptors enhances the GABA receptor-mediated spontaneous IPSCs in MTCs. Second, CCK does not affect the action potential independent miniature IPSCs in MTCs. Third, CCK potentiates glomerular inhibition resulting in increased GABA receptor-mediated presynaptic inhibition of olfactory nerve terminals and enhanced spontaneous IPSCs in MTCs and glomerular neurons. Fourth, CCK enhances miniature IPSCs in the excitatory external tufted cells, although neither in the inhibitory short axon cells (SACs) nor in periglomerular cells (PGCs). Finally, CCK excites all tested SACs and a very small minority of GABAergic neurons in the granule cell layer or in periglomerular cells, but not in deep SACs. These results demonstrate that CCK selectively activates SACs to engage the SAC-formed interglomerular circuit and thus elevates inhibition broadly in the OB glomerular layer. This modulation may prevent the system from saturating in response to a high concentration of odourants or facilitate the detection of weak stimuli by increasing signal-to-noise ratio.

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Dendritic Release of Neurotransmitters

Cited by 54 publications

References 273 publications

Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration

Activation of the rat hypothalamic supramammillary nucleus by food anticipation, food restriction or ghrelin administration

High-throughput evolution of near-infrared serotonin nanosensors

Cholecystokinin selectively activates short axon cells to enhance inhibition of olfactory bulb output neurons

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