Role of central muscarinic cholinergic systems in food motor conditioning

1971 ◽  
Vol 72 (4) ◽  
pp. 1166-1169
Author(s):  
V. V. Vinogradov ◽  
S. S. Krylov
1980 ◽  
Vol 239 (6) ◽  
pp. H713-H720 ◽  
Author(s):  
E. Muscholl

Activation of muscarinic cholinergic receptors located at the terminal adrenergic nerve fiber inhibits the process of exocytotic norepinephrine (NE) release. This neuromodulatory effect of acetylcholine and related compounds has been discovered as a pharmacological phenomenon. Subsequently, evidence for a physiological role of the presynaptic muscarinic inhibition was obtained on organs known to be innervated by the autonomic ground plexus (Hillarp, Acta. Physiol. Scand. 46, Suppl. 157: 1-68, 1959) in which terminal adrenergic and cholinergic axons run side by side. Thus, in the heart electrical vagal stimulation inhibits the release of NE evoked by stimulation of sympathetic nerves, and this is reflected by a corresponding decrease in the postsynaptic adrenergic response. On the other hand, muscarinic antagonists such as atropine enhance the NE release evoked by field stimulation of tissues innervated by the autonomic ground plexus. The presynaptic muscarine receptor of adrenergic nerve terminals probably restricts the influx of calcium ions that triggers the release of NE. However, the sequence of events between recognition of the muscarinic compound by the receptor and the process of exocytosis still remains to be clarified.


2015 ◽  
Vol 113 (3) ◽  
pp. 796-807 ◽  
Author(s):  
Ricardo Hernández-Martínez ◽  
José J. Aceves ◽  
Pavel E. Rueda-Orozco ◽  
Teresa Hernández-Flores ◽  
Omar Hernández-González ◽  
...  

The external globus pallidus (GPe) is central for basal ganglia processing. It expresses muscarinic cholinergic receptors and receives cholinergic afferents from the pedunculopontine nuclei (PPN) and other regions. The role of these receptors and afferents is unknown. Muscarinic M1-type receptors are expressed by synapses from striatal projection neurons (SPNs). Because axons from SPNs project to the GPe, one hypothesis is that striatopallidal GABAergic terminals may be modulated by M1 receptors. Alternatively, some M1 receptors may be postsynaptic in some pallidal neurons. Evidence of muscarinic modulation in any of these elements would suggest that cholinergic afferents from the PPN, or other sources, could modulate the function of the GPe. In this study, we show this evidence using striatopallidal slice preparations: after field stimulation in the striatum, the cholinergic muscarinic receptor agonist muscarine significantly reduced the amplitude of inhibitory postsynaptic currents (IPSCs) from synapses that exhibited short-term synaptic facilitation. This inhibition was associated with significant increases in paired-pulse facilitation, and quantal content was proportional to IPSC amplitude. These actions were blocked by atropine, pirenzepine, and mamba toxin-7, suggesting that receptors involved were M1. In addition, we found that some pallidal neurons have functional postsynaptic M1 receptors. Moreover, some evoked IPSCs exhibited short-term depression and a different kind of modulation: they were indirectly modulated by muscarine via the activation of presynaptic cannabinoid CB1 receptors. Thus pallidal synapses presenting distinct forms of short-term plasticity were modulated differently.


2018 ◽  
Vol 30 (12) ◽  
pp. 1803-1820 ◽  
Author(s):  
Marieke Jepma ◽  
Stephen B. R. E. Brown ◽  
Peter R. Murphy ◽  
Stephany C. Koelewijn ◽  
Boukje de Vries ◽  
...  

To make optimal predictions in a dynamic environment, the impact of new observations on existing beliefs—that is, the learning rate—should be guided by ongoing estimates of change and uncertainty. Theoretical work has proposed specific computational roles for various neuromodulatory systems in the control of learning rate, but empirical evidence is still sparse. The aim of the current research was to examine the role of the noradrenergic and cholinergic systems in learning rate regulation. First, we replicated our recent findings that the centroparietal P3 component of the EEG—an index of phasic catecholamine release in the cortex—predicts trial-to-trial variability in learning rate and mediates the effects of surprise and belief uncertainty on learning rate (Study 1, n = 17). Second, we found that pharmacological suppression of either norepinephrine or acetylcholine activity produced baseline-dependent effects on learning rate following nonobvious changes in an outcome-generating process (Study 1). Third, we identified two genes, coding for α2A receptor sensitivity ( ADRA2A) and norepinephrine reuptake ( NET), as promising targets for future research on the genetic basis of individual differences in learning rate (Study 2, n = 137). Our findings suggest a role for the noradrenergic and cholinergic systems in belief updating and underline the importance of studying interactions between different neuromodulatory systems.


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