SYMPOSIUM: BEHAVIOR MODIFICATION BY DRUGS

PEDIATRICS ◽  
1972 ◽  
Vol 49 (5) ◽  
pp. 694-701
Author(s):  
Ross J. Baldessarini

The pharmacology of the amphetamines has been studied for several decades. There is now a great deal of information about their tissue distribution and catabolism, largely by enzymatic oxidative processes. The most clearly characterized actions of the amphetamines occur at catecholamineconaining nerve terminals and tend to enhance the availability of the transmitter to post-synaptic receptors. The actions of the drugs in the CNS include stimulation of the ascending reticular formation of the brainstem, and probably enhancement of the activity of a behavior reinforcement system mediated by the median forebrain bundle. Toxic effects of amphetamine include apparent interactions at the basal ganglia to produce stereotyped behaviors in animals and man. All of these actions might involve catecholaminergic synaptic transmission systems. Under careful, controlled medical supervision the amphetamines are remarkably safe, although in excessive doses they can produce severe toxic, sympathomimetic and psychotic effects and can be lethal. They are subject to gross abuses, and to habituation. Tolerance develops to some of their actions, but usually not to their legitimate and rational uses in narcolepsy and hyperkinesis. Withdrawal symptoms are relatively minor.

2020 ◽  
Author(s):  
Inga Boll ◽  
Pia Jensen ◽  
Veit Schwämmle ◽  
Martin R. Larsen

AbstractSynaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show a novel potential modulator of synaptic transmission, sialylation of N-linked glycosylation. The negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after five seconds depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.


2020 ◽  
Vol 19 (9) ◽  
pp. 1418-1435
Author(s):  
Inga Boll ◽  
Pia Jensen ◽  
Veit Schwämmle ◽  
Martin R. Larsen

Synaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show that sialylation of N-linked glycosylation is a novel potential modulator of neurotransmitter release mechanisms by investigating depolarization-dependent changes of formerly sialylated N-linked glycopeptides. We suggest that negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after 5 s depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Veronica Ghiglieri ◽  
Vincenza Bagetta ◽  
Valentina Pendolino ◽  
Barbara Picconi ◽  
Paolo Calabresi

In Parkinson’s disease (PD), alteration of dopamine- (DA-) dependent striatal functions and pulsatile stimulation of DA receptors caused by the discontinuous administration of levodopa (L-DOPA) lead to a complex cascade of events affecting the postsynaptic striatal neurons that might account for the appearance of L-DOPA-induced dyskinesia (LID). Experimental models of LID have been widely used and extensively characterized in rodents and electrophysiological studies provided remarkable insights into the inner mechanisms underlying L-DOPA-induced corticostriatal plastic changes. Here we provide an overview of recent findings that represent a further step into the comprehension of mechanisms underlying maladaptive changes of basal ganglia functions in response to L-DOPA and associated to development of LID.


2021 ◽  
Author(s):  
A.N. Kadenov ◽  
O.V. Yakovleva

Hydrogen sulfide is one of the gas-transmitters that also performs other biological functions. The antioxidant property of this substance is one of the important ones. The research was conducted on rats of both sexes between 6 and 18 days of age. We have shown that the offspring of females injected subcutaneously with hydrogen sulfide increased the area and luminescence of nerve terminals during postnatal ontogenesis, which can be further used to level the effects of hyperhomocysteinemia on synaptic transmission. Key words: neuromuscular synapse, fluorescent microscopy, hydrogen sulfide.


1997 ◽  
Vol 77 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Carlota Largo ◽  
Geoffrey C. Tombaugh ◽  
Peter G. Aitken ◽  
Oscar Herreras ◽  
George G. Somjen

Largo, Carlota, Geoffrey C. Tombaugh, Peter G. Aitken, Oscar Herreras, and George G. Somjen. Heptanol but not fluoroacetate prevents the propagation of spreading depression in rat hippocampal slices. J. Neurophysiol. 77: 9–16, 1997. We investigated whether heptanol and other long-chain alcohols that are known to block gap junctions interfere with the generation or the propagation of spreading depression (SD). Waves of SD were triggered by micro-injection of concentrated KCl solution in stratum (s.) radiatum of CA1 of rat hippocampal tissue slices. DC-coupled recordings of extracellular potential ( V o) were made at the injection and at a second site ∼1 mm distant in st. radiatum and sometimes also in st. pyramidale. Extracellular excitatory postsynaptic potentials (fEPSPs) were evoked by stimulation of the Schaffer collateral bundle; in some experiments, antidromic population spikes were evoked by stimulation of the alveus. Bath application of 3 mM heptanol or 5 mM hexanol completely and reversibly prevented the propagation of the SD-related potential shift (Δ V o) without abolishing the Δ V o at the injection site. Octanol (1 mM) had a similar but less reliably reversible effect. fEPSPs were depressed by ∼30% by heptanol and octanol, 65% by hexanol. Antidromic population spikes were depressed by 30%. In isolated, patch-clamped CA1 pyramidal neurons, heptanol partially and reversibly depressed voltage-dependent Na currents possibly explaining the slight depression of antidromic spikes and, by acting on presynaptic action potentials, also the depression of fEPSPs. Fluoroacetate (FAc), a putative selective blocker of glial metabolism, first induced multiple spike firing in response to single afferent volleys and then severely suppressed synaptic transmission (confirming earlier reports) without depressing the antidromic population spike. FAc did not inhibit SD propagation. The effect of alkyl alcohols is compatible with the idea that the opening of normally closed neuronal gap junctions is required for SD propagation. Alternative possible explanations include interference with the lipid phase of neuron membranes. The absence of SD inhibition by FAc confirms that synaptic transmission is not necessary for the propagation of SD, and it suggests that normally functioning glial cells are not essential for SD generation or propagation.


2001 ◽  
Vol 1 ◽  
pp. 11-11
Author(s):  
David Poyner ◽  
Heather Cater ◽  
Nick Hartell ◽  
Alex Conner ◽  
Debbie Hay ◽  
...  

The best characterised signalling pathway activated by both CGRP and adrenomedullin is stimulation of adenylate cyclase via Gs. However, it is clear that in some circumstances the peptides can activate other signal transduction pathways, e.g., increases in intracellular calcium. Many of these signalling pathways can be observed in cultured cells but it is important also to examine isolated tissues to discover the full repertoire of transduction events. In the rat cerebellum there are receptors that respond to both CGRP and adrenomedullin. These seem to be located postsynaptically on Parallel Fibre nerve terminals and modulate transmission to Purkinje cells. Adrenomedullin acts via cAMP, apparently to augment neurotransmitter release. By contrast, CGRP decreases transmitter release, via a non-cAMP mediated pathway. We are currently examining the role of NO and tyrosine kinases in the responses to these peptides.


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