Neurotensin afferents of the ventral tegmental area in the rat: [1] re‐examination of their origins and [2] responses to acute psychostimulant and antipsychotic drug administration

Geisler, Stefanie; Zahm, Daniel S.

doi:10.1111/j.1460-9568.2006.04928.x

Cited by 67 publications

(72 citation statements)

References 74 publications

(107 reference statements)

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“…If this hypothesis (Figure 4) is correct, GABAergic LPO outputs can convert the RMTg to a facilitator of midbrain dopaminergic activity, complementing its better known role as a dopaminergic suppressor (Barrot and Thome, 2011;Bourdy and Barrot, 2012) in response mainly (at least as is known so far) to input from the lateral habenula (Jhou et al, 2009a, b). Unfortunately, aside from glutamatergic (Geisler et al, 2007) and neurotensinergic (Zahm et al, 2001;Geisler and Zahm, 2006) projections to the VTA, the phenotypes of LPO outputs to the mesopontine tegmentum, and their projection specificities remain to be revealed.…”

Section: Discussionmentioning

confidence: 99%

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

Lavezzi

Parsley

Zahm

2014

Neuropsychopharmacol

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The rostromedial tegmental nucleus (RMTg) is a strong inhibitor of dopamine neurons in the ventral tegmental area (VTA) reported to influence neurobiological and behavioral responses to reward omission, aversive and fear-eliciting stimuli, and certain drugs of abuse. Insofar as previous studies implicate ventral mesencephalic dopamine neurons as an essential component of locomotor activation, we hypothesized that the RMTg also should modulate locomotion activation. We observed that bilateral infusions into the RMTg of the gamma-aminobutyric acid A (GABA A ) agonist, muscimol, indeed activate locomotion. Alternatively, bilateral RMTg infusions of the GABA A receptor antagonist, bicuculline, suppress robust activations of locomotion elicited in two distinct ways: (1) by disinhibitory stimulation of neurons in the lateral preoptic area and (2) by return of rats to an environment previously paired with amphetamine administration. The possibility that suppressive locomotor effects of RMTg bicuculline infusions were due to unintended spread of drug to the nearby VTA was falsified by a control experiment showing that bilateral infusions of bicuculline into the VTA produce activation rather than suppression of locomotion. These results objectively implicate the RMTg in the regulation of locomotor activation. The effect is important because much evidence reported in the literature suggests that locomotor activation can be an involuntary behavioral expression of expectation and/or want without which the willingness to execute adaptive behaviors is impaired.

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Section: Discussionmentioning

confidence: 99%

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

Lavezzi

Parsley

Zahm

2014

Neuropsychopharmacol

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“…The combination of WGA-apo HRP-gold in tracing with nonisotopic in situ hybridization was discussed recently (JongenRelo and Amaral, 2000;Geisler and Zahm, 2006b). Visualization of the tracer by silver enhancement does not interfere with nonisotopic in situ hybridization and results in a punctiform, high-contrast black signal.…”

Section: Methodological Considerationsmentioning

confidence: 99%

“…Hybridizations were performed as described in detail recently (Geisler and Zahm, 2006b). Briefly, after immersing entire series of free-floating sections for 15 min in acetic anhydride (1.5% triethanolamine, 0.42% HCl, 0.25% acetic anhydride in H 2 O), the series were placed for 30 min in hybridization buffer (50% formamide, 300 mM sodium chloride, 20 mM Tris, pH 7.4, 1 mM EDTA, 10% dextran sulfate, and 1ϫ Denhardt's reagent) and thereafter into hybridization buffer containing 0.1% SDS, 0.1% sodium thiosulfate, salmon sperm DNA (0.1 mg/ml), yeast total RNA (0.25 mg/ml), yeast tRNA (0.25 mg/ml), and the cRNA antisense and sense probes for VGLUTs 1 and 2 (at a concentration of 500 ng/ml) and for VGLUT3 (at a concentration of 400 ng/ml).…”

Section: Introductionmentioning

confidence: 99%

Glutamatergic Afferents of the Ventral Tegmental Area in the Rat

Geisler¹,

Derst²,

Veh³

et al. 2007

J. Neurosci.

420

425

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Glutamatergic inputs to the ventral tegmental area (VTA), thought crucial to the capacity of the VTA to detect and signal stimulus salience, have been reported to arise in but a few structures. However, the afferent system of the VTA comprises very abundant neurons within a large formation extending from the prefrontal cortex to the caudal brainstem. Neurons in nearly all parts of this continuum may be glutamatergic and equivalently important to VTA function. Thus, we sought to identify the full range of glutamatergic inputs to the VTA by combining retrograde transport of wheat germ agglutinin-bound gold after injections into the VTA with nonisotopic in situ hybridization of the vesicular glutamate transporters (VGLUTs) 1, 2, and 3. We found glutamatergic neurons innervating the VTA in almost all structures projecting there and that a majority of these are subcortical and VGLUT2 mRNA positive. The tremendous convergence of glutamatergic afferents from many brain areas in the VTA suggests that (1) the function of the VTA requires integration of manifold and diverse bits of information and (2) the activity of the VTA reflects the ongoing activities of various combinations of its afferents.

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“…Mesolimbic projections, from A10 (in the VTA), provide a dense dopaminergic innervation to ventral striatopallidum, and, to a lesser extent, the extended amygdala (CeA, bed nucleus of stria terminalis and associated structures), as well as to a number of other sites in the basal forebrain, such as the septum and preoptic region. All of these structures project back to A10 directly, but this forms but part of the A10 afferent system, which comprises a nearly continuous and extensively interconnected formation of structures extending from the prefrontal cortex to the caudal brainstem [53][54][55][56] . Mesolimbic dopaminergic projections are reported to be involved in a broad range of functions, including locomotor activation (e.g., Ref.…”

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confidence: 99%

The Dopaminergic Projection System, Basal Forebrain Macrosystems, and Conditioned Stimuli

Zahm¹,

Trimble²

2008

CNS spectr.

Self Cite

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This review begins with a description of some problems that in recent years have beset an influential circuit model of fear-conditioning and goes on to look at neuroanatomy that might subserve conditioning viewed in a broader perspective, including not only fear, but also appetitive, conditioning. The paper then focuses on basal forebrain functional-anatomical systems, or macrosystems, as they have come to be called, which Lennart Heimer and colleagues described beginning in the 1970's. Yet more specific attention is then given to the relationships of the dorsal and ventral striatopallidal systems and extended amygdala with the dopaminergic mesotelencephalic projection systems, culminating with the hypothesis that all macrosystems contribute to behavioral conditioning.There is tremendous current interest in the neurobiological mechanisms underlying conditioned fear stemming in large part from an increasing prevalence in American culture of anxiety and panic disorders, not to mention PTSD 1 . By 2000, the relevant brain circuitry had seemed to be satisfactorily described 2 , but a number of serious caveats had been voiced the preceding year 3 , and an unraveling process accelerated thereafter. Indeed, current theory on the neural substrates of fear conditioning has entered into a state of reassessment 4 .The essential elements of fear conditioning are described by the observation that pairing neutral and fear-arousing stimuli causes the neutral one to gain meaning such that it can then drive an organism's voluntary and involuntary actions. Thus, behaviorally, rats exposed to a brief tone followed immediately by a footshock will soon, frequently after a single trial, come to "freeze" upon hearing the tone. In LeDoux's 2 model of this phenomenon, neuroplasticity reflecting the attachment of "significance" to a neutral stimulus, i.e., heralding the transformation of neutral to conditioned stimulus (CS), occurs in the amygdala, specifically its lateral nucleus (LA). According to LeDoux's model, LA projects to another part of the amygdala, the central nucleus (CeA), which, in turn sends out divergent descending projections to somatic and autonomic motor effectors in the brainstem, eliciting behavioral freezing and accompanying autonomic responses. Consistent with the model, [1] sensory inputs bearing information about the aversive and neutral (to be conditioned) stimuli converge in LA 5 , and [2] an increase in the efficacy of CS-related synapses corresponds to conditioning [6][7][8] . But, soon it was realized that the CeA consists of two parts, a medial division (CeAm) from which most of its descending projections arise and to which LA does not project, and a lateral one (CeAl) to which it does. While CeAl projects to CeAm and thus might serve as a relay interposed between LA and CeAm, the CeAl to CeAm projection is nearly exclusively inhibitiory (GABAergic) and thus would inhibit rather than activate outputs to brainstem. The model was accordingly adjusted to emphasize instead a projection from LA to amygda...

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Neurotensin afferents of the ventral tegmental area in the rat: [1] re‐examination of their origins and [2] responses to acute psychostimulant and antipsychotic drug administration

Cited by 67 publications

References 74 publications

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

Modulation of Locomotor Activation by the Rostromedial Tegmental Nucleus

Glutamatergic Afferents of the Ventral Tegmental Area in the Rat

The Dopaminergic Projection System, Basal Forebrain Macrosystems, and Conditioned Stimuli

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