5-HT1A and 5-HT4 receptor colocalization on hippocampal pyramidal cells

Roychowdhury, Sushovan; Haas, Helmut L.; Anderson, Edmund G.

doi:10.1016/0028-3908(94)90086-8

Cited by 53 publications

(30 citation statements)

References 19 publications

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“…Previous in vitro electrophysiological studies have shown that applications of 5-HT onto the CA1 pyramidal neurons produce both hyperpolarization and deporalization through the activation of 5-HT 1A and 5-HT 4 receptors, respectively (Chaput et al 1990;Andrade and Chaput 1991;Roychowdhury et al 1994;Torres et al 1995). It has been also demonstrated that, in the presence of WAY-100635, the 5-HT applications solely facilitate the firing activity through stimulating 5-HT 4 receptors, in vitro Pugliese et al 1998).…”

Section: Discussionmentioning

confidence: 99%

Endogenous 5-HT Tonically Inhibits Spontaneous Firing Activity of Dorsal Hippocampus CA1 Pyramidal Neurons Through Stimulation of 5-HT1A Receptors in Quiet Awake Rats In Vivo Electrophysiological Evidence

Kasamo

2001

Neuropsychopharmacology

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The present study was performed to examine an overall effect of endogenous serotonin (5-HT) on the spontaneous firing activity of the dorsal hippocampus CA1 pyramidal neurons in quiet awake rats. A selective 5-HT 1A antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide (WAY-100635: 0.03-0.2 mg/kg, s.c.) It has been shown that there are at least 14 serotonin (5-HT; 5-hydroxytryptamine) receptor subtypes over seven distinct receptor subfamilies. Among these seven receptor subfamilies, only the 5-HT 1 subfamily is inhibitory whereas the others are excitatory (see Hoyer et al. 1994; Glennon and Dukat 1995 for reviews). Several in situ hybridization studies have demonstrated that ten of these 14 receptor subtypes are detectable over the CA1 region of the rat hippocampus (see Andrade 1998 for review).In accordance with the distribution and exuberance of 5-HT receptors expressed in this area, several in vitro electrophysiological studies have demonstrated multiple actions of 5-HT on the excitability of the CA1 pyramidal neurons. These are the direct inhibitory and exci- 142 K. Kasamo et al. N EUROPSYCHOPHARMACOLOGY 2001 -VOL . 24 , NO . 2 tatory actions through stimulating 5-HT 1A and 5-HT 4 receptors on the pyramidal neurons, respectively. In addition, via inhibitory interneurons, 5-HT indirectly decreases and increases the excitability through stimulating 5-HT 2 and 5-HT 3 , and 5-HT 1A receptors, respectively (see Hoyer et al. 1994; Aghajanian 1995; Andrade 1998 for reviews). Given these extremely diverse actions of 5-HT demonstrated in vitro , endogenous 5-HT should produce multiple actions simultaneously on the excitability of the CA1 pyramidal neurons in vivo. These in vitro data have been obtained with the preparations isolated from various potentially confounding factors, such as the effects of activation of other receptor systems. Contrary, in vivo cells in the brain are exposed continuously to the various neurotransmitter, neuromodulator and hormonal stimuli. In any cell, these stimuli are integrated spatially and temporally. Furthermore, the intracellular signaling cascades are extensively interconnected. Moreover, even in vivo , the use of anesthesia drastically reduces the 5-HT tone (Jacobs 1985; as well as the spontaneous firing activity of the hippocampus pyramidal neurons (Blier et al. 1993). The reduction in the firing activity indicates that the use of anesthesia per se markedly decreases the excitability of hippocampal pyramidal neurons. Thus, an overall action of endogenous 5-HT on the firing activity of the pyramidal neurons in awake rats is unpredictable solely basing on the data obtained from in vivo studies with anesthetized animals and from in vitro experiments. Therefore, using awake animals is essential to scrutinize the influence of endogenous 5-HT. To our knowledge, such studies examining the net effect of endogenous 5-HT on cellular activity in the brain of awake rats have not been performed so far.Thus, the present study was carried out to...

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Section: Discussionmentioning

confidence: 99%

Endogenous 5-HT Tonically Inhibits Spontaneous Firing Activity of Dorsal Hippocampus CA1 Pyramidal Neurons Through Stimulation of 5-HT1A Receptors in Quiet Awake Rats In Vivo Electrophysiological Evidence

Kasamo

2001

Neuropsychopharmacology

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“…The synaptic transmission between hippocampal pyramidal cells is unaffected or inhibited by 5-HT (Tokarski and Bijak 1996;Mlinar et al, 2001). Serotonin also changes excitability of the pyramidal cells and its immediate effects are mostly inhibitory (Segal, 1981;Roychowdhury et al, 1994;Tokarski and Bijak, 1996). Thus, in the presence of 5-HT, a relative contribution of the mossy fiber input to excitation of the pyramidal cells is increased.…”

Section: Discussionmentioning

confidence: 99%

“…There is dense projection of serotonergic fibers to the hippocampus (Jacobs and Azmitia, 1992), and serotonin [5-hydroxytriptamine (5-HT)] has been shown to modulate neuronal excitability and/or synaptic transmission in all subregions of the hippocampus (Segal, 1981;Otmakhov and Bragin, 1982;Roychowdhury et al, 1994;Tokarski and Bijak 1996;Mlinar et al, 2001;Otmakhova et al, 2005). The serotonergic system in the hippocampus is modulated by repeated SSRI treatments, which includes changes in effects of 5-HT application (Tokarski and Bijak 1996;Bijak et al, 1997) and serotonergic afferent stimulation (Chaput et al, 1991), downregulation of the 5-HT transporter (Benmansour et al, 2002), and enhanced tonic inhibition mediated by 5-HT 1A receptors (Haddjeri et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Chronic Fluoxetine Bidirectionally Modulates Potentiating Effects of Serotonin on the Hippocampal Mossy Fiber Synaptic Transmission

Kobayashi¹,

Ikeda²,

Haneda³

et al. 2008

Journal of Neuroscience

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Selective serotonin reuptake inhibitors (SSRIs) have been used to treat various psychiatric disorders. Although the cellular mechanisms underlying amelioration of particular symptoms are mostly unknown, recent studies have shown critical importance of the dentate gyrus of the hippocampus in behavioral effects of SSRIs in rodents. Here, we show that serotonin potentiates synaptic transmission between mossy fibers, the sole output of the dentate granule cells, and CA3 pyramidal cells in mouse hippocampal slices. This potentiation is mediated by activation of 5-HT 4 receptors and intracellular cAMP elevation. A chronic treatment of mice with fluoxetine, a widely used SSRI, bidirectionally modulates the 5-HT-induced potentiation: Fluoxetine enhances the potentiation induced by lower concentrations of serotonin, while attenuates that by the higher concentration, which represents stabilization of synaptic 5-HT action. In contrast to the chronic treatment, an acute application of fluoxetine in slices induces a leftward shift in the dose-response curve of the 5-HT-induced potentiation. Thus, acute and chronic fluoxetine treatments have distinct effects on the serotonergic modulation of the mossy fiber synaptic transmission. Exposure of mice to novel environments induces increases in locomotor activity and hippocampal extracellular 5-HT levels. In mice chronically treated with fluoxetine, the novelty-induced hyperactivity is reduced without significant alterations in home cage activity and motor skills. Our results suggest that the chronic fluoxetine treatment can stabilize the serotonergic modulation of the central synaptic transmission, which may contribute to attenuation of hyperactive behaviors.

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“…Later, it was reported that 5-HT suppresses long term potentiation (LTP) in hippocampal slices by preventing the activation of NMDA receptors and the enhancement of AMPA-mediated currents that lead to LTP induction [171]. The hippocampus contains several subtypes of serotonin receptors, namely 5-HT 1A [160,174], 5HT 1B [4,130], 5-HT 2 [17,28], 5-HT 3 [116,132], 5-HT 4 [5,160], 5-HT 6 and 5-HT 7 [73], many of which modulate glutamate-mediated transmission acting at different levels. In the CA1 region, pre-synaptic 5-HT 1A receptors reduce glutamate release from Schaffer collaterals to CA1 pyramidal neurons [162] (Fig.…”

Section: Modulation Of Glutamate Transmissionmentioning

confidence: 99%

Serotonin as a Modulator of Glutamate- and GABA-Mediated Neurotransmission: Implications in Physiological Functions and in Pathology

Ciranna

2006

267

170

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Abstract:The neurotransmitter serotonin (5-HT), widely distributed in the central nervous system (CNS), is involved in a large variety of physiological functions. In several brain regions 5-HT is diffusely released by volume transmission and behaves as a neuromodulator rather than as a "classical" neurotransmitter. In some cases 5-HT is co-localized in the same nerve terminal with other neurotransmitters and reciprocal interactions take place. This review will focus on the modulatory action of 5-HT on the effects of glutamate and -amino-butyric acid (GABA), which are the principal neurotransmitters mediating respectively excitatory and inhibitory signals in the CNS. Examples of interaction at preand/or post-synaptic levels will be illustrated, as well as the receptors involved and their mechanisms of action. Finally, the physiological meaning of neuromodulatory effects of 5-HT will be briefly discussed with respect to pathologies deriving from malfunctioning of serotonin system.

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5-HT1A and 5-HT4 receptor colocalization on hippocampal pyramidal cells

Cited by 53 publications

References 19 publications

Endogenous 5-HT Tonically Inhibits Spontaneous Firing Activity of Dorsal Hippocampus CA1 Pyramidal Neurons Through Stimulation of 5-HT1A Receptors in Quiet Awake Rats In Vivo Electrophysiological Evidence

Endogenous 5-HT Tonically Inhibits Spontaneous Firing Activity of Dorsal Hippocampus CA1 Pyramidal Neurons Through Stimulation of 5-HT1A Receptors in Quiet Awake Rats In Vivo Electrophysiological Evidence

Chronic Fluoxetine Bidirectionally Modulates Potentiating Effects of Serotonin on the Hippocampal Mossy Fiber Synaptic Transmission

Serotonin as a Modulator of Glutamate- and GABA-Mediated Neurotransmission: Implications in Physiological Functions and in Pathology

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