Cholinergic innervation of the rat hippocampus as revealed by choline acetyltransferase immunocytochemistry: A combined light and electron microscopic study

Frotscher, Michael; Léránth, Csaba

doi:10.1002/cne.902390210

Cited by 563 publications

(285 citation statements)

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“…Scale bar: 5 m. figured in conventional PSDs but rather are more distributed and respond to agonist supplied more diffusely. This would be consistent with suggestions that cholinergic innervation in the CNS, such as that provided by the septal input to the hippocampus, may be diffuse, delivering ACh at a distance for "volume transmission" (McKinney et al, 1983;Frotscher and Leranth, 1985;Descarries et al, 1997;Descarries, 1998;Zoli et al, 1999; but see Turrini et al, 2001). Because ␣7-nAChRs can also respond to choline as an agonist (Papke et al, 1996;Alkondon et al, 1997b), hydrolysis of ACh by extracellular acetylcholinesterase need not prevent distally released agonist from affecting the receptors.…”

Section: Postsynaptic/perisynaptic Sitessupporting

confidence: 82%

Nicotinic α7 receptors: Synaptic options and downstream signaling in neurons

2002

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Nicotinic receptors are cation-ion selective ligand-gated ion channels that are expressed throughout the nervous system. Most have significant calcium permeabilities, enabling them to regulate calcium-dependent events. One of the most abundant is a species composed of the ␣7 gene product and having a relative calcium permeability equivalent to that of NMDA receptors. The ␣7-containing receptors can be found presynaptically where they modulate transmitter release, and postsynaptically where they generate excitatory responses. They can also be found in perisynaptic locations where they modulate other inputs to the neuron and can activate a variety of downstream signaling pathways. The effects the receptors produce depend critically on the sites at which they are clustered. Instructive preparations for examining ␣7-containing receptors are the rat hippocampus, where they are thought to play a modulatory role, and the chick ciliary ganglion, where they participate in throughput transmission as well as regulatory signaling. Relatively high levels of ␣7-containing receptors are found in the two preparations, and the receptors display a variety of synaptic options and functions in the two cases. Progress is starting to be made in understanding the mechanisms responsible for localizing the receptors at specific sites and in identifying components tethered in the vicinity of the receptors that may facilitate signal transduction and downstream signaling.

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Section: Postsynaptic/perisynaptic Sitessupporting

confidence: 82%

Nicotinic α7 receptors: Synaptic options and downstream signaling in neurons

2002

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“…ACh is known to evoke multiple effects in hippocampal neurons and the cholinergic influences on the evoked responses are strongly dependent on the sites of application (Bernardo and Prince 1982;Cherubini et al 1982;Frotscher and Léranth 1985;Madison et al 1987;Benson et al 1988;Chen and Tonegawa 1997). Several lines of evidence show that the cholinergic system plays a role in facilitating plastic changes at Schaffer collateral-commissural-CA1 synapses in accordance with the well-known memory-facilitating action of ACh (Markram and Segal 1990;Auerbach and Segal 1994).…”

Section: Pacap-38 Enhances Ca1 Synaptic Transmissionmentioning

confidence: 86%

“…Cold Krnjevic and Ropert 1982;Frotscher and Léranth 1985;Hepler et al 1985;Madison et al 1987). ACh is known to evoke multiple effects in hippocampal neurons and the cholinergic influences on the evoked responses are strongly dependent on the sites of application (Bernardo and Prince 1982;Cherubini et al 1982;Frotscher and Léranth 1985;Madison et al 1987;Benson et al 1988;Chen and Tonegawa 1997).…”

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confidence: 99%

“…PACAP-38, acting through type-I receptors, enhances the ACh sensitivity of ciliary ganglionic neurons by a cAMPdependent mechanism (Matthews et al 1987). The hippocampus receives abundant extrinsic cholinergic innervation from the medial septal area (Frotscher and Léranth 1985;Matthews et al 1987), and the septohippocampal choliner-gic pathway has been suggested to have an important role in learning and memory (Valentino and Dingledine 1981;Krnjevic and Ropert 1982;Hepler et. al.…”

mentioning

confidence: 99%

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PACAP-38 Enhances Excitatory Synaptic Transmission in the Rat Hippocampal CA1 Region

Roberto¹,

Brunelli²

2000

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Specific receptors for pituitary adenylate cyclase-activating polypeptide (PACAP), a novel peptide with neuroregulatory and neurotrophic functions, have been identified recently in different brain regions, including the hippocampus. In this study, we examined the effects of PACAP-38 on the excitatory postsynaptic field potentials (fEPSPs) evoked at the Schaffer collateral-CA1 synapses. Brief bath application of PACAP-38 (0.05 nM) induced a long-lasting facilitation of the basal transmission. Enhancement of this response was occluded in part by previous high-frequency-induced long-term potentiation (LTP). PACAP-38 did not significantly alter the paired-pulse facilitation (PPF). PACAP-38 has been shown to have a presynaptic effect on the septohippocampal cholinergic terminals, which results in an increase in basal acetylcholine (ACh) release. To assess whether the PACAP-38 enhancement of CA1 synapses was related to the activation of the cholinergic system we examined the effect of this peptide in the presence of atropine, a muscarinic receptor antagonist. The enhancement of the fEPSPs by PACAP-38 was blocked by bath application of atropine. These results show that PACAP-38 induces facilitation of hippocampal synaptic transmission through activation of the cholinergic system via the muscarinic receptors.Pituitary adenylate cyclase-activating polypeptide (PACAP) is a new member of a neuropeptide family that includes vasoactive intestinal peptide (VIP), glucagon, secretin, and growth hormone, and whose members are thought to play an important role in neuronal function (Miyata et al. 1989; Arimura 1998). PACAP has been isolated from the ovine hypothalamus on the basis of its ability to stimulate adenylate cyclase in rat anterior pituitary cells (Miyata et al. 1989) and it is present in the central nervous system (CNS) and in a variety of peripheral tissues (Masuo et al. 1992;Arimura and Shioda 1995;Shioda et al. 1997). Two distinct forms of this neuropeptide, PACAP-38 and PACAP-27, with 38 or 27 amino acids, respectively, have been characterized (Arimura and Shioda 1995). PACAP-38 and PACAP-27 possess similar biological activity (Miyata et al. 1990). PACAP-38 is the prevailing form in mammalian tissues (Arimura 1992). The amino-acid sequence of PACAP-38 is well-preserved in different species and is identical in sheep, rats, and humans (Arimura 1992). Two types of high-affinity PACAP receptors have been identified: The PACAP type-I receptor (PACAPRI), which specifically binds PACAP-38 and PACAP-27 with higher affinity than it binds VIP; and the PACAP type-II receptor (PACAPRII), which has high homology with the VIP receptor and binds PACAP-38, PACAP-27, and VIP with the same high affinity (Arimura 1992;Sokolov and Kleschevnikov 1995). PACAPRI is mainly distributed in the CNS, including the septum, hippocampus, cerebellar cortex, amygdala, nucleus accumbens, hypothalamus, and the entorhinal cortices (Masuo et al. 1992(Masuo et al. ,1993 and it is positively coupled to adenylate cyclase and phospholipase C, whereas PACA...

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“…Furthermore, a subpopulation of hippocampal cells either discharges at low frequency or in the theta-frequency range, depending on level of cholinergic innervation of the hippocampus (Bland and Colom, 1993;Steriade et al, 1993). The theta rhythm in vivo is thought to depend on the cholinergic and GABAergic septal inputs (Brazh-nik and Fox, 1997;Freund and Antal, 1988;Frotscher and Leranth, 1985;Stewart and Fox, 1990). The frequency of the theta rhythm is controlled by GABAergic phasic inputs from the septum, while its power is controlled by septal cholinergic afferents (Brazhnik et al, 1993;Lee et al, 1994;Soltesz and Deschenes, 1993;Stewart and Fox, 1990;Ylinen et al, 1995).…”

Section: Introductionmentioning

confidence: 99%