Mechanism of the galanin induced increase in acetylcholine release in vivo from striata of freely moving rats

Amoroso, D.; Girotti, Prisca; Fisone, Gilberto; Bartfai, Tamás; Consolo, S.

doi:10.1016/0006-8993(92)91158-b

Cited by 11 publications

(11 citation statements)

References 37 publications

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“…(3 nmol in 10 μl) caused a statistically significant but short‐lasting increase (100%) in the basal ACh in the striatum and a long lasting increase (100%) when galanin was perfused continuously through the microdialysis probe (Ögren & Pramanik, 1991a,b; Pramanik & Ögren, 1992). In contrast to the results obtained in awake animals (Amoroso et al , 1992), the results in the anaesthetized rats did not indicate any additive effect after the co‐administration of galanin with scopolamine compared to that of scopolamine alone (Ögren & Pramanik, 1991b; Pramanik & Ögren, 1993). The above results indicated that galanin induces a prominent increase in the basal ACh release in the striatum in both anaesthetized and freely moving rats, but the results obtained after co‐administration of galanin with scopolamine appeared to differ.…”

Section: Introductionmentioning

confidence: 84%

“…Consistent with this notion is the observation that galanin given i.c.v. was shown to induce a long lasting increase in striatal ACh release in awake rats when the excitatory corticostriatal input was removed (Amoroso et al , 1992). However, the most important factor may be the enhancement of GABAergic inhibitory activity mediated via the GABA A type of receptors in the striatum (Harris et al , 1995).…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, galanin given i.c.v. was shown to induce a transient increase in striatal ACh release in awake female rats (Amoroso et al , 1992). These differential effects obtained in awake rats may depend on the different microdialysis probes used (concentric versus transversal probes), different solvents of galanin, different sexes of animals and in particular different routes of administration (perfusion at a constant rate versus i.c.v.…”

Section: Discussionmentioning

confidence: 99%

“…In the rat striatum, on the other hand, galanin has been shown to stimulate the basal release of ACh (Ögren & Pramanik 1991a,b; Amoroso et al , 1992; Pramanik & Ögren, 1992; 1993). In this structure, galanin given i.c.v., (3.12 nmol in 15 μl) was found to induce a transient increase (50%) in the basal ACh release in freely moving rats while a long lasting increase (60%) was seen only when the corticostriatal input was removed (Amoroso et al , 1992). The same authors found that scopolamine given s.c. produced an increase in the basal ACh release in cortically lesioned rats and that the co‐administration of galanin (i.c.v.)…”

Section: Introductionmentioning

confidence: 99%

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Differential effects of the neuropeptide galanin on striatal acetylcholine release in anaesthetized and awake rats

Αντωνίου

Kehr

Snitt

et al. 1997

British J Pharmacology

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1 In the present study the mechanisms were examined by which the neuropeptide galanin modulates the extracellular concentrations of striatal acetylcholine (ACh) in en¯urane anaesthetized and in freely moving male rats by use of in vivo microdialysis and high performance liquid chromatography. 2 The perfusion of galanin through the microdialysis probe (0.3 nmol ml 71 ,¯ow rate: 2 ml min 71 ) caused a statistically signi®cant increase in the basal striatal ACh levels in anaesthetized but a decrease in awake animals. No signi®cant eect was revealed after a low dose (0.1 nmol ml 71 ,¯ow rate: 2 ml min 71 ) of galanin perfusion. Both the stimulating and inhibitory eects of galanin on basal ACh release were reversible. 3 The muscarinic antagonist scopolamine (0.1 mg kg 71 , subcutaneously (s.c.)) caused a signi®cant increase in ACh release in both anaesthetized and awake animals. 4 The combination of galanin plus scopolamine attenuated the stimulant eect on ACh release caused by scopolamine alone in awake animals. 5 The putative galanin receptor antagonist M35 at 0.3 nmol ml 71 but not at 0.1 nmol ml 71 caused a signi®cant reduction (20%) in ACh release, supporting the view that M35 at higher concentrations behaves as a partial agonist at the galanin receptor. When M35 (0.1 nmol ml 71 ) was co-infused with galanin (0.3 nmol ml 71) the galanin-evoked decrease in ACh release was completely blocked. 6 Taken together, these results indicate that galanin aects basal ACh release via stimulation of galanin receptors within the striatum. The mechanism involved is dependent on the anaesthesia procedure which may act via enhancement of g-aminobutyric acid A (GABA A ) mediated transmission within striatal and/or output neurones. In addition, anaesthesia may also decrease the activity of glutamatergic striatal aerents. The results with M35 indicate that the role of galanin perfused in striatum is permissive in the normal rat. Furthermore, galanin is a potent inhibitory modulator of basal ACh release also in the striatum, as recently was shown in the ventral hippocampus in awake animals.

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Section: Introductionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Differential effects of the neuropeptide galanin on striatal acetylcholine release in anaesthetized and awake rats

Αντωνίου

Kehr

Snitt

et al. 1997

British J Pharmacology

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“…Pharmacological experiments that examine transmitter release are less clear on the predominantly inhibitory effects observed at a cellular level. For example, galanin inhibits acetylcholine (ACh) release in the rat ventral hippocampus and from slices of the cerebral cortex (Fisone et al 1987;Wang et al 1999), whereas it is stimulates ACh release in the rat striatum (Amorso et al 1992;Pramanik and Ogren 1993).…”

Section: Introductionmentioning

confidence: 99%

Novel Excitatory Actions of Galanin on Rat Cholinergic Basal Forebrain Neurons: Implications for Its Role in Alzheimer's Disease

Jhamandas

Harris

MacTavish

et al. 2002

Journal of Neurophysiology

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. Novel excitatory actions of galanin on rat cholinergic basal forebrain neurons: implications for its role in Alzheimer's disease. J Neurophysiol 87: 696 -704, 2002; 10.1152/jn. 00416.2001. Galanin, a 29-amino-acid neuropeptide, is generally viewed as an inhibitory neuromodulator in a variety of central systems. Galanin expression is upregulated in the cholinergic basal forebrain nuclei in Alzheimer's disease (AD) and is postulated to play an important role in memory and cognitive function. In this study, application of galanin to acutely dissociated rat neurons from the basal forebrain nucleus diagonal band of Broca (DBB), caused a decrease in whole cell voltage-activated currents in a majority of cells. Galanin reduces a suite of potassium currents, including calcium-activated potassium (I C ), the delayed rectifier (I K ), and transient outward potassium (I A ) conductances, but not calcium or sodium currents. Under current-clamp conditions, application of galanin evoked an increase in excitability and a loss of accommodation in cholinergic DBB neurons. Using single-cell RT-PCR technique, we determined that galanin actions were specific to cholinergic, but not GABAergic DBB neurons The notion that galanin plays a deleterious role in AD is based, in part, on galanin hyperinnervation of cholinergic cells in the basal forebrain of AD patients, its ability to depress acetylcholine release and its inhibitory actions at other CNS sites. However, our results suggest that by virtue of its excitatory actions on cholinergic neurons, galanin may in fact play a compensatory role by augmenting the release of acetylcholine from remaining cholinergic basal forebrain neurons. This action might serve to delay the progression of AD pathology linked to a reduction in central cholinergic tone.

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Hypothermia induced by cholinomimetic drugs is blocked by galanin: possible involvement of ATP-sensitive K+ channels

Patel

Hutson

1994

European Journal of Pharmacology

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Mechanism of the galanin induced increase in acetylcholine release in vivo from striata of freely moving rats

Cited by 11 publications

References 37 publications

Differential effects of the neuropeptide galanin on striatal acetylcholine release in anaesthetized and awake rats

Differential effects of the neuropeptide galanin on striatal acetylcholine release in anaesthetized and awake rats

Novel Excitatory Actions of Galanin on Rat Cholinergic Basal Forebrain Neurons: Implications for Its Role in Alzheimer's Disease

Hypothermia induced by cholinomimetic drugs is blocked by galanin: possible involvement of ATP-sensitive K+ channels

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