Differential membrane properties and dopamine effects in the shell and core of the rat nucleus accumbens studied in vitro

Pennartz, Cyriel M. A.; Weel, M.J. Dolleman-van der; Silva, F.H. Lopes da

doi:10.1016/0304-3940(92)90660-y

Cited by 90 publications

(44 citation statements)

References 15 publications

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“…The core and the shell differ in anatomical, neurochemical and electrophysiological characteristics (eg Pennartz et al, 1992;Jongen-Rêlo et al, 1994;Heimer et al, 1997;Groenewegen et al, 1999;Zahm, 2000). Moreover, subterritorial differences in cocaine-induced neuroadaptations have been observed in previous studies (eg Sorg et al, 1995;Robinson et al, 2001;Thomas et al, 2001;Ricci et al, 2004;Brenhouse and Stellar, 2006).…”

Section: Core Vs Shellmentioning

confidence: 98%

Accumbal Neurons that are Activated during Cocaine Self-Administration are Spared from Inhibitory Effects of Repeated Cocaine Self-Administration

Peoples

Kravitz

Lynch

et al. 2006

Neuropsychopharmacol

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Hypoactivity of the accumbens is induced by repeated cocaine exposure and is hypothesized to play a role in cocaine addiction. However, it is difficult to understand how a general hypoactivity of the accumbens, which facilitates multiple types of motivated behaviors, could contribute to the selective increase in drug-directed behavior that defines addiction. Electrophysiological recordings, made during sessions in which rats self-administer cocaine, show that most accumbal neurons that encode events related to drugdirected behavior achieve and maintain higher firing rates during the period of cocaine exposure (Task-Activated neurons) than do other accumbal neurons (Task-Non-Activated neurons). We have hypothesized that this difference in activity makes the neurons that facilitate drug-directed behavior less susceptible than other neurons to the chronic inhibitory effects of cocaine. A sparing of neurons that facilitate drug-directed behavior from chronic hypoactivity might lead to a relative increase in the transmission of neuronal signals that facilitate drug-directed behavior through accumbal circuits and thereby contribute to changes in behavior that characterize addiction (ie differential inhibition hypothesis). A prediction of the hypothesis is that neurons that are activated in relation to task events during cocaine self-administration sessions will show less of a decrease in firing across repeated self-administration sessions than will other neurons. To test this prediction, rats were exposed to 30 daily (6 h/day) cocaine self-administration sessions. Chronic extracellular recordings of single accumbal neurons were made during the second to third session and the 30th session. Between-session comparisons showed that decreases in firing were exhibited by Task-Non-Activated, but not by Task-Activated, neurons. During the day 30 session, the magnitude of the difference in firing rate between the two groups of neurons was positively related to the propensity of animals to seek and take cocaine. The findings of the present study are consistent with a basic prediction of the differential inhibition hypothesis and may be relevant to understanding cocaine addiction.

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Section: Core Vs Shellmentioning

confidence: 98%

Accumbal Neurons that are Activated during Cocaine Self-Administration are Spared from Inhibitory Effects of Repeated Cocaine Self-Administration

Peoples

Kravitz

Lynch

et al. 2006

Neuropsychopharmacol

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“…More specifically, in the nucleus accumbens, a shell region and a core region can be distinguished on the basis of immunohistochemical features (Zà borszky et al, 1985;Zahm and Brog, 1992;Jongen-Rêlo et al, 1994). The differences between shell and core appear to be reflected in their input-output relationships and morphological, neurochemical, electrophysiological, and behavioral properties (see, e.g., Heimer et al, 1991;Berendse et al, 1992;Deutch and Cameron, 1992;Meredith et al, 1992;Pennartz et al, 1992;Zahm and Brog, 1992;Brog et al, 1993;Zahm and Heimer, 1993;Maldonado-Irizarry and Kelley, 1994;Prinssen et al, 1994;Wright and Groenewegen, 1995). Therefore, we examined the distribution of 5-HT 2a mRNA in different striatal (sub)regions through densitometry of autoradiograms obtained with isotopic in situ hybridization.…”

mentioning

confidence: 98%

Regional and cellular distribution of serotonin 5-hydroxytryptamine2a receptor mRNA in the nucleus accumbens, olfactory tubercle, and caudate putamen of the rat

Mijnster¹,

Raimundo²,

Koskuba³

et al. 1997

J. Comp. Neurol.

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This paper describes the regional and cellular distribution of serotonin 5-hydroxytryptamine2a (5-HT2a) receptor mRNA in (sub)regions of the rat striatum by using in situ hybridization. Our results indicate that 5-HT2a mRNA is distributed heterogeneously in this brain region. Regional densitometry of autoradiograms from striatal sections hybridized with isotope-labeled cRNA probes showed that mRNA levels were highest in the olfactory tubercle, lower in the nucleus accumbens, and lowest in the caudate-putamen. In the nucleus accumbens, the average mRNA levels in the shell were higher than those in the core. These data suggest a particular relevance for the 5-HT2a receptor for olfactory tubercle- and shell-related functions. Therefore, in the nucleus accumbens and the olfactory tubercle, the cellular localization of 5-HT2a mRNA was investigated by determining the colocalization of 5-HT2a mRNA with enkephalin mRNA or dynorphin mRNA. 5-HT2a mRNA was found in enkephalinergic as well as dynorphinergic neurons. Thus, there does not seem to be a differential distribution of this receptor in the output routes of the ventral striatum. In all of the subregions investigated (core, medial shell, and lateral shell of the nucleus accumbens and the olfactory tubercle), only subpopulations of the total enkephalinergic and dynorphinergic populations were found to contain 5-HT2a mRNA. For enkephalin, the percentage colocalization was higher in the lateral shell (61%) compared with the other subregions (38-45%). For dynorphin, the percentage colocalization was higher in the olfactory tubercle (68%) than in the other subregions (34-43%). The differences in (sub)regional mRNA levels and in colocalization with opioids suggest a considerable regional differentiation in the effects of 5-HT2a-mediated neurotransmission in the striatum.

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“…Corticostriatal, presumably glutamatergic, terminals contact the heads of spines that often receive DA synapses on their necks (Totterdell and Smith, 1989;Meredith and Wouterlood, 1990;Sesack and Pickel, 1990). Since the DA input appears to modulate the corticostriatal input (Brown and Arbuthnott, 1983;Pennartz et al, 1992a), its removal may produce excitotoxic conditions that result in spine loss. Certainly, small increases of glutamate underlie spine swelling and loss in hippocampal slices (Siman and Card, 1988).…”

Section: Potential Mechanisms Underlying Dendritic Remodelingmentioning

confidence: 99%

Effects of dopamine depletion on the morphology of medium spiny neurons in the shell and core of the rat nucleus accumbens

1995

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Nucleus accumbens receives a dense dopaminergic innervation which is important in regulating motivated states of behavior such as goal- directed actions, stimulus-reward associations and reinforcement of addictive substances. The shell and core territories of this nucleus each receive functionally and morphologically distinct dopaminergic inputs and lesions of the ascending pathways totally deprive the core but not the shell of dopaminergic fibers. Medium spiny neurons are the principal targets of dopaminergic terminals. The present study explored whether the loss of dopamine inputs can affect these neurons and whether cells in the shell and core would be equally susceptible to such a loss. Intracellular injection in fixed slices and neuronal reconstruction were used to analyze the dendritic trees of 62 neurons in the shell and core of animals that received a unilateral, chronic 6- hydroxydopamine lesion of the medial forebrain bundle. In the dopamine- depleted core, dendrites are significantly shorter (16% decrease) than in the intact core and in both the dopamine-depleted core and lateral shell, dendrites are less spiny than in respective control regions. Dopamine loss in the medial shell is associated with significantly more tortuous dendrites that are lower in spine density. However, the number of spines is not reduced which may mean that the increase recorded for segment length, although insignificant in tests, could be responsible for the change in spine density. These data suggest that the loss of dopamine can affect accumbal neuronal morphology and, moreover, can affect neuronal structures differentially in the shell and core.

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Differential membrane properties and dopamine effects in the shell and core of the rat nucleus accumbens studied in vitro

Cited by 90 publications

References 15 publications

Accumbal Neurons that are Activated during Cocaine Self-Administration are Spared from Inhibitory Effects of Repeated Cocaine Self-Administration

Accumbal Neurons that are Activated during Cocaine Self-Administration are Spared from Inhibitory Effects of Repeated Cocaine Self-Administration

Regional and cellular distribution of serotonin 5-hydroxytryptamine2a receptor mRNA in the nucleus accumbens, olfactory tubercle, and caudate putamen of the rat

Effects of dopamine depletion on the morphology of medium spiny neurons in the shell and core of the rat nucleus accumbens

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