Regional distribution of choline acetyltransferase and acetylcholinesterase within the amygdaloid complex and stria terminalis system

doi:10.1016/0006-8993(77)90397-3

Brain Research

Volume 120, Issue 3, 28 January 1977, Pages 435-445

https://doi.org/10.1016/0006-8993(77)90397-3 Get rights and content

Abstract

The distribution of ‘marker’ enzymes for cholinergic neurons has been studied in 10 subdivisions of the amygdaloid complex of the rat brain. Choline acetyltransferase activity was measured using a radiochemical method in samples dissected from fresh serial sections. Acetylcholinesterase was studied using a histochemical procedure. Both enzymes had similar patterns of distribution within the amygdaloid complex and were most concentrated in the posterior lateral and basolateral nuclei and in the nucleus of the lateral olfactory tract. These enzymes were much less concentrated in the cortical, medial, central, and basomedial nuclei. Large differences in acetylcholinesterase staining were found within the lateral posterior and the basolateral nuclei and within the pyriform cortex. Biochemical studies showed a parallel distribution of choline acetyltransferase within these nuclei. The results indicate that cholinergic neural elements in the amygdala are concentrated primarily in the basolateral complex and suggest that this region may be innervated by cholinergic fibers traveling in the ventral amygdalo-fugal pathway.

Reference (31)

Ben-AriY. et al.
Regional distribution of tyrosine hydroxylase, norepinephrine and dopamine within the amygdaloid complex of the rat
Brain Research
(1975)
BrownsteinM. et al.
Norepinephrine and dopamine in the limbic system of the rat
Brain Research
(1974)
KataokaK. et al.
Habenulo-interpeduncular tract: a possible cholinergic in rat brain
Brain Research
(1973)
McEwenB.S. et al.
Factors influencing sex hormone uptake by rat brain regions. I. Effects of neonatal treatment hypophysectomy competing steroid on estradiol uptake
Brain Research
(1970)
PalkovitsM.
Isolated removal of hypothalamic or other brain nuclei of the rat
Brain Research
(1973)
PalkovitsM. et al.
Choline acetyltransferase content of limbic nuclei of the rat
Brain Research
(1974)
Ben-AriY. et al.
Regional distribution of glutamic acid decar☐ylase and GABA within the amygdaloid complex and stria terminalis system of the rat
J. Neurochem.
(1976)
Ben-AriY. et al.
Regional distribution of choline acetyltransferase and acetyl cholinesterase within the amygdaloid complex of the rat
J. Physiol. (Lond.)
(1976)
BrodalA.
The amygdaloid nucleus in the rat
J. comp. Neurol.
(1947)
CowanW.M. et al.
The connections of the amygdala
J. Neurol. Neurosurg. Psychiat.
(1965)

De OlmosJ.

The amygdaloid projection field in the rat as studied with the cupric-silver method

FonnumF.

Radiochemical micro assays for the determination of choline acetyltransferase and acetylcholinesterase activities

Biochem. J.

(1969)

FoxC.A.

Certain basal telencephalic centers in the cat

J. comp. Neurol.

(1940)

GirgisM.

Distribution of cholinesterase in the basal rhinencephalic structures of the coypu (Myocaster coypus)

J. comp. Neurol.

(1968)

GirgisM.

Distribution of cholinesterase in the basal rhinencephalic structures of the grivet monkey (Cercopithecus aethiops)

Acta anat. (Basel)

(1968)

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A number of modulatory systems are involved in regulating BLA excitability, mainly by affecting the excitability state of the principal cells and/or the GABAergic interneurons. The cholinergic input to the amygdala from the basal forebrain appears to be of major importance in this regard, as suggested by the remarkably dense cholinergic innervation of the BLA (Mesulam et al., 1992), its exceptionally high AChE activity (Ben-Ari et al., 1977; Prager et al., 2013, 2014), as well as the increase in anxiety-like behavior when the function of the basal forebrain is disrupted (Martinowich et al., 2012). The most well known behavioral evidence for the importance of the cholinergic system in the regulation of amygdalar function comes from the symptoms of Alzheimer's disease, where anxiety is prevalent (Espana et al., 2010; Ferretti et al., 2001).
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But it is also possible that the cholinergic system has a more significant role in the regulation of the excitability of the BLA, compared to the hippocampus and piriform cortex, and thus cholinergic hyperactivity in the BLA is more likely to produce hyperexcitability and seizures. The exceptionally dense cholinergic innervation of the BLA (Mesulam et al., 1992), its markedly high concentration of AChE (Ben-Ari et al., 1977 and present study), and the high expression of muscarinic receptors – which play a primary role in seizure initiation by nerve agents (Skovira et al., 2010) – on BLA pyramidal cells (McDonald and Mascagni, 2010), may be attesting to the prominent role that the cholinergic system plays in the regulation of the BLA excitability. Why AChE activity in the BLA of the no-SE rats was not significantly inhibited remains to be determined.
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Presynaptic muscarinic M <inf>2</inf> receptors modulate glutamatergic transmission in the bed nucleus of the stria terminalis
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Stress has also been shown to increase ACh release in limbic structures (Fadda et al., 2000; Mark et al., 1996; Nail-Boucherie et al., 2000; Tajima et al., 1996), where it is thought to play a critical role in modulating cognition, attention, and synaptic plasticity (Hasselmo and Barkai, 1995; Ovsepian et al., 2004). Several markers for cholinergic terminals are expressed in the BNST, namely choline acetyltransferase (ChAT), and acetylcholinesterase (AChE) (Ben-Ari et al., 1977; Gaspar et al., 1985; Prensa et al., 2003; Ruggiero et al., 1990; Woolf and Butcher, 1982), suggesting that local ACh release may play an important role in modulating the activity of neurons in this region. The response to ACh is mediated by activation of either muscarinic receptors (mAChR) or nicotinic receptors (nAChR), and high levels of muscarinic receptors have been detected in the BNST (Kobayashi et al., 1978; Kushida et al., 1995; Spencer et al., 1986; Wamsley et al., 1984).
The anterolateral cell group of the bed nucleus of the stria terminalis (BNST_ALG) serves as an important relay station in stress circuitry. Limbic inputs to the BNST_ALG are primarily glutamatergic and activity-dependent changes in this input have been implicated in abnormal behaviors associated with chronic stress and addiction. Significantly, local infusion of acetylcholine (ACh) receptor agonists into the BNST trigger stress-like cardiovascular responses, however, little is known about the effects of these agents on glutamatergic transmission in the BNST_ALG. Here, we show that glutamate- and ACh-containing fibers are found in close association in the BNST_ALG. Moreover, in the presence of the acetylcholinesterase inhibitor, eserine, endogenous ACh release evoked a long-lasting reduction of the amplitude of stimulus-evoked EPSCs. This effect was mimicked by exogenous application of the ACh analog, carbachol, which caused a reversible, dose-dependent, reduction of the evoked EPSC amplitude, and an increase in both the paired-pulse ratio and coefficient of variation, suggesting a presynaptic site of action. Uncoupling of postsynaptic G-proteins with intracellular GDP-β-S, or application of the nicotinic receptor antagonist, tubocurarine, failed to block the carbachol effect. In contrast, the carbachol effect was blocked by prior application of atropine or M₂ receptor-preferring antagonists, and was absent in M₂/M₄ receptor knockout mice, suggesting that presynaptic M₂ receptors mediate the effect of ACh. Immunoelectron microscopy studies further revealed the presence of M₂ receptors on axon terminals that formed asymmetric synapses with BNST neurons. Our findings suggest that presynaptic M₂ receptors might be an important modulator of the stress circuit and hence a novel target for drug development.

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^**: Present address: Department of Pharmacology, Harvard Medical School, Boston, Mass. 02115, U.S.A.

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Regional distribution of choline acetyltransferase and acetylcholinesterase within the amygdaloid complex and stria terminalis system

Abstract

Brain Research

Brain Research

Brain Research

Brain Research

Brain Research

Brain Research

Regional distribution of glutamic acid decar☐ylase and GABA within the amygdaloid complex and stria terminalis system of the rat

J. Neurochem.

Regional distribution of choline acetyltransferase and acetyl cholinesterase within the amygdaloid complex of the rat

J. Physiol. (Lond.)

The amygdaloid nucleus in the rat

J. comp. Neurol.

The connections of the amygdala

J. Neurol. Neurosurg. Psychiat.

The amygdaloid projection field in the rat as studied with the cupric-silver method

Radiochemical micro assays for the determination of choline acetyltransferase and acetylcholinesterase activities

Biochem. J.

Certain basal telencephalic centers in the cat

J. comp. Neurol.

Distribution of cholinesterase in the basal rhinencephalic structures of the coypu (Myocaster coypus)

J. comp. Neurol.

Distribution of cholinesterase in the basal rhinencephalic structures of the grivet monkey (Cercopithecus aethiops)

Acta anat. (Basel)