Racial Differences in Misclassification of Healthy Eating Based on Food Frequency Questionnaire and 24-Hour Dietary Recalls

OBJECTIVES

To examine the agreement in nutrient intake and alternate healthy eating indices (AHEI) between a self-administered Food Frequency Questionnaire (FFQ) and 24-hour recall (24HR) measurements of diet by race, among urban older women.

DESIGN

Cross-sectional observational study.

SETTING

Urban neighborhoods in Washington, DC, USA.

PARTICIPANTS

Community-dwelling White and Black women aged 65 and older.

MEASUREMENTS

In 2014 and 2015, 49 White and 44 Black older women were queried on diet using both FFQ and 24-hour recalls. The correlation coefficients of 55 nutrient intake measures and agreements on healthy eating classification between the two instruments were compared overall and by race.

RESULTS

The mean correlation coefficient (rho) was 0.46 for Whites and 0.23 for Blacks. For 47 measures, rho was lower for Blacks. Whites had a strong correlation of ≥0.5 for 28 items, while Blacks had strong correlations for only 3 items. Based on FFQ, the mean (SD) of AHEI were 54.0 (10.3) for Whites and 45.9 (8.8) for Blacks (p<0.001). Based on 24HR, the mean (SD) were 43.9 (10.8) for Whites and 33.2 (9.6) for Blacks (p<0.001). Using 32 as the cutoff (40% of maximum AHEI score), 50% of Blacks and 14% of Whites were classified as eating unhealthy based on the 24HR, versus 2.6% and 0% based on the FFQ.

CONCLUSION

The FFQ has limited ability to accurately assess nutrient intake among older Black women, and tends to underestimate racial differences in healthy eating. The FFQ should be further improved for use in racial disparities research of healthy eating in older age, using a larger sample of older women with racial and geographic diversities.

Racial Differences in Eating Patterns and Food Purchasing Behaviors among Urban Older Women

OBJECTIVE

To examine differences in diet and food purchasing behaviors between Black and White older women living in urban neighborhoods.

DESIGN

Cross-sectional observational study.

SETTING

Urban neighborhoods in Washington, DC, USA.

PARTICIPANTS

Community-dwelling White and Black women of age 65 and older.

MEASUREMENTS

Participants were queried on diet via 24-hour recalls, food purchasing habits, their use of neighborhood resources and local travel patterns. Frequency and location of self-reported food purchasing and consumption were compared by race.

RESULTS

In 2014 and 2015, 49 White and 44 Black older women were enrolled in the study. Compared to Whites, Blacks reported lower daily caloric intake (mean (SD) 1314 (404) vs. 1529 (448), p=0.02), with a higher percent of calories from protein and fat 1.8 (7.0), p=0.03), and a slightly higher polyunsaturated to saturated fat ratio (p=0.05). Blacks had substantially lower alternate healthy eating index (AHEI) (33.5 (10.2) vs. 43.9 (10.8) of 80 possible points, p<0.001), daily intake (grams) of total fiber (15.3 (8.1) vs. 22.9 (8.5), p<0.001), insoluble fiber (10.8 (6.9) vs. 15.9 (6.5), p<0.001), and soluble fiber (4.5 (2.0) vs. 6.9 (2.8), p<0.001). Blacks had lower intake of micronutrients, alcohol and caffeine. Blacks shopped for groceries less often (4.4 (3.0) vs. 6.2 (3.0) monthly; p=0.006) and spent a longer time traveling to stores (15.8 (9.1) vs. 11.5 (7.2) minutes per trip, p=0.02). A lower percent of Blacks walked to stores (14% vs. 40%, p=0.003) and a higher percent of Blacks rode in a car with someone else (33% vs. 6%, p<0.001).

CONCLUSIONS

In an urban setting, food consumption and purchasing behaviors differed substantially between older Black and White women, which should be further investigated and considered to promote healthy eating in older populations.

Gender and Age Differences in Levels, Types and Locations of Physical Activity among Older Adults Living in Car-Dependent Neighborhoods

BACKGROUND

A thorough understanding of gender differences in physical activity is critical to effective promotion of active living in older adults.

OBJECTIVES

To examine gender and age differences in levels, types and locations of physical activity.

DESIGN

Cross-sectional observation.

SETTING

Car-dependent urban and rural neighborhoods in Worcester County, Massachusetts, USA.

PARTICIPANTS

111 men and 103 women aged 65 years and older.

MEASUREMENTS

From 2012 to 2014, participants were queried on type, frequency and location of physical activity. Participants wore an accelerometer for 7 consecutive days.

RESULTS

Compared to women, men had a higher mean daily step count (mean (SD) 4385 (2122) men vs. 3671(1723) women, p=0.008). Men reported higher frequencies of any physical activity and moderate-to-vigorous physical activity, and a lower frequency of physical activity inside the home. Mean daily step counts and frequency of physical activity outside the home decreased progressively with age for both men and women. Women had a sharper decline in frequencies of self-reported physical activity. Men had a significant decrease in utilitarian walking, which women did not (p=0.07). Among participants who reported participation in any physical activity (n=190), more women indicated exercising indoors more often (59% vs. 44%, p=0.04). The three most commonly cited locations for physical activity away from home for both genders were streets or sidewalks, shopping malls, and membership-only facilities (e.g., YMCA or YWCA). The most common types of physical activity, performed at least once in a typical month, with over 40% of both genders reporting, included light housework, brisk walking, leisurely walking, and stretching.

CONCLUSION

Levels, types and location preferences of physical activity differed substantially by gender. Levels of physical activity decreased progressively with age, with greater decline among women. Consideration of these gender differences is necessary to improve the effectiveness of active living promotion programs among older adults.

Tumor necrosis factor alpha: activity dependent expression and promotion of cortical column sleep in rats

Cortical surface evoked potentials (SEPs) are larger during sleep and characterize a sleep-like state in cortical columns. Since tumor necrosis factor alpha (TNF) may be involved in sleep regulation and is produced as a consequence of waking activity, we tested the hypothesis that direct application of TNF to the cortex will induce a sleep-like state within cortical columns and enhance SEP amplitudes. We found that microinjection of TNF onto the surface of the rat somatosensory cortex enhanced whisker stimulation-induced SEP amplitude relative to a control heat-inactivated TNF microinjection. We also determined if whisker stimulation enhanced endogenous TNF expression. TNF immunoreactivity (IR) was visualized after 2 h of deflection of a single whisker on each side. The number of TNF-IR cells increased in layers II-IV of the activated somatosensory barrel column. In two separate studies, unilateral deflection of multiple whiskers for 2 h increased the number of TNF-IR cells in layers II-V in columns that also exhibited enhanced cellular ongogene (Fos-IR). TNF-IR also colocalized with NeuN-IR suggesting that TNF expression was in neurons. Collectively these data are consistent with the hypotheses that TNF is produced in response to neural activity and in turn enhances the probability of a local sleep-like state as determined by increases in SEP amplitudes.

Fos-immunoreactivity in the hypothalamus: dependency on the diurnal rhythm, sleep, gender, and estrogen

Diurnal variations and sleep deprivation-induced changes in the number of Fos-immunoreactive (Fos-IR) neurons in various hypothalamic/preoptic nuclei were studied in the rat. The nuclei implicated in sleep regulation, the ventrolateral preoptic (VLPO), median preoptic (MnPO), and suprachiasmatic (SCN, dorsomedial subdivision) nuclei, displayed maximum c-fos expression in the rest (light) period. Sleep deprivation (S.D.) suppressed Fos-IR in the dorsomedial subdivision of SCN but failed to alter Fos in the VLPO. Fos-IR increased in the VLPO during recovery after S.D. A nocturnal rise in Fos expression was detected in the arcuate (ARC), anterodorsal preoptic (ADP) and anteroventral periventricular (AVPV) nuclei whereas the lateroanterior hypothalamic nucleus (LA) and the ventrolateral subdivision of SCN did not display diurnal variations. S.D. stimulated Fos expression in the ARC, ADP, and LA. Statistically significant, albeit modest, differences were noted in the number of Fos-IR cells between males and cycling female (estrus/diestrus) in the VLPO, MnPO, ARC, LA, and AVPV, and the female ADP did not display diurnal variations. Ovariectomy (OVX) was followed by marked reduction in Fos expression in the VLPO, SCN, and AVPV, and the diurnal rhythm decreased in the VLPO, and vanished in the dorsomedial SCN, and AVP. Estrogen administration to OVX female rats stimulated Fos expression in most nuclei, and the lost diurnal variations reoccurred. In contrast, castration of male rats had little effect on Fos expression (slight rises in diurnal Fos in the ARC and ventrolateral SCN). The results suggest that Fos expression is highly estrogen-dependent in many hypothalamic nuclei including those that have been implicated in sleep regulation.

Conflict resolution at the end of life

OBJECTIVE

Limited empirical research has examined how decisions are made when the preferences of terminally ill patients conflict with physicians' recommendations. This study sought to investigate physicians' strategies for resolving conflicts with dying patients.

DESIGN

Cross-sectional, qualitative interviews.

SUBJECTS

Subjects were 158 physicians caring for at least one terminally ill patient.

SETTING

University medical center.

MEASUREMENTS AND MAIN RESULTS

We analyzed physicians' responses to the open-ended interview questions, "How do you handle a situation when a patient wants a treatment that you believe does not provide any benefit?" and "How do you handle a situation when a patient does not want a treatment you think would be beneficial?" For patient requests of nonbeneficial treatments, physicians reported the following as important: negotiating with and educating patients (71%), deferring to patient requests for benign or uncomplicated treatments (34%), convincing patients to forgo treatments (33%), refusing patient requests for nonbeneficial treatment (22%), using family influence (16%), not offering futile treatments (13%), and referring to other physicians for disputed care (9%). Potential harm (23%) and cost of treatment (18%) were reasons cited for withholding treatments. In response to patient refusals of beneficial treatments, physicians report the following as important: negotiating with patients (59%), convincing patients to receive treatment (41%), assessing patient competence (32%), using family influence (27%), and referring to other physicians (21%).

CONCLUSIONS

Physicians vary in the communication and negotiation strategies they use when their medical judgment conflicts with dying patients' preferences. Medical ethicists could play a greater role in teaching ethically important communication skills. Physicians providing care at the end of life report strategies for respecting patients that reflect graduated degrees of accommodation tailored to the costliness and riskiness of requests; they are most accepting of patient requests for benign, technically easy, inexpensive, and medically effective treatments.

Sleep modifies glutamate decarboxylase mRNA within the barrel cortex of rats after a mystacial whisker trim

STUDY OBJECTIVES

Determine the effects of time of day and sleep deprivation on glutamate decarboxylase 67,000 MW (GAD67) mRNA during cortical synaptic reorganization induced by a unilateral trimming of the mystacial vibrissae in rats.

DESIGN

Two experiments were conducted--One measured GAD67 mRNA in the barrel cortex at 3 or 6 h after a unilateral whisker cut at either light or dark onset; the other measured GAD67 mRNA after a unilateral whisker cut at light onset with or without sleep deprivation.

SETTING

University-based Research Laboratory.

PARTICIPANTS

Sprague-Dawley rats (250-350 g).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

The reverse transcriptase polymerase chain reaction was used to measure the time of day changes in GAD67 mRNA after a unilateral whisker cut. GAD67 mRNA decreased in the barrel cortex at 3 and 6 h after a whisker trim at dark onset when the rats were mainly awake. No changes were observed in GAD67 mRNA levels after a whisker cut at light onset, a time when the rats mainly sleep. In situ hybridization for GAD67 mRNA supported these findings; no changes in GAD mRNA occurred in layer 4 of the barrel cortex that received input from the mystacial whiskers that were trimmed at light onset. However, when the rats were sleep-deprived, GAD67 mRNA increased in the barrel cortex receiving input from the lip hairs surrounding the trimmed mystacial whiskers.

CONCLUSIONS

These data imply that sleep modifies GAD67 mRNA expression and that this effect is dependent upon the nature of the ongoing synaptic reorganization. They support the notion that sleep serves a synaptic function.

Sleep deprivation but not a whisker trim increases nerve growth factor within barrel cortical neurons

Sleep is hypothesized to influence activity-driven changes in the brain microcircuitry. A change in the barrel cortex following the removal of the mystacial whiskers in rats is a model for synaptic plasticity. This model was combined with sleep deprivation and immunoreactivity for nerve growth factor (NGF) was determined. Sleep deprivation for 6 h after light onset significantly increased the number of NGF-immunoreactive pyramidal neurons in layer V of the barrel cortex. However, unilateral trimming of mystacial whiskers did not affect NGF immunoreactivity in the contralateral or ipsilateral barrel cortices when rats were allowed to sleep. If the rats received a unilateral whisker cut at light onset, and subsequently were deprived of sleep, increases in the NGF-immunoreactive neurons were only observed in the barrel cortex on the side that received input from the remaining intact whiskers. In contrast, NGF immunoreactivity on the side contralateral to the cut whiskers decreased in sleep-deprived animals to levels below those observed in the control animals that were allowed to sleep. These results suggest that NGF expression is influenced by the interaction of sleep, afferent input and the nature of ongoing synaptic reorganization. Further, results are consistent with the hypothesis that growth factors, such as NGF, form part of the mechanism responsible for sleep regulation and that they also form one facet of sleep-related synaptic plasticity.

The involvement of the mediodorsal nucleus of the thalamus and the midbrain extrapyramidal area in locomotion elicited from the ventral pallidum

Motor activity is regulated by projections from the nucleus accumbens to the ventral pallidum, but it is unclear which efferents regulate behavioral output from the ventral pallidum. Motor activity was elicited pharmacologically by microinjecting either the mu opioid receptor agonist, Tyr-D-Ala-Gly-NmePhe-Gly-OH (DAMGO) or the glutamate receptor agonist, alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) into the ventral pallidum. The involvement of efferent projections was determined by microinjecting the local anesthetic procaine into the mediodorsal nucleus of the thalamus (MD) or the midbrain extrapyramidal area (MEA) prior to administering DAMGO or AMPA into the ventral pallidum. The motor activity induced by DAMGO was blocked by procaine microinjected into either the MD or the MEA. In contrast, procaine microinjected into the MD did not block motor activity elicited by AMPA while procaine into the MEA abolished the behavioral activation. These data indicate that the involvement of efferent projections from the ventral pallidum to either the MD or MEA in motor activation depends upon the type of receptor stimulated in the ventral pallidum.

Involvement of the pallidal-thalamocortical circuit in adaptive behavior

Interconnections among the ventral mesencephalon, nucleus accumbens, and ventral pallidum are critical in the initiation of adaptive behavioral responses to environmental stimuli. Within this circuit are two highly topographically organized subcircuits that are differentially interconnected with limbic and motor circuitry in the brain. However, there is not a great deal of anatomical interconnection between the limbic and motor subcircuits. A polysynaptic connection between the two subcircuits involves projections from the limbic ventral pallidum to the mediodorsal thalamus to the prefrontal cortex back to the motor regions of the nucleus accumbens. In the present report we show that this connection is critical in the expression of motor behavior elicited by opioids and the capacity of a rat to perform in a task requiring spatial working memory.

Repeated cocaine alters glutamate receptor subunit levels in the nucleus accumbens and ventral tegmental area of rats that develop behavioral sensitization

Increased glutamate transmission in the nucleus accumbens and ventral tegmental area has been proposed as a mechanism underlying sensitized behavioral responses to repeated cocaine administration. GluR1, GluR2/3, and NMDAR1 subunits of glutamate receptors were quantified from immunoblots in these brain nuclei in rats at 24 h and 3 weeks after discontinuing 1 week of daily cocaine injections. Motor behavior was monitored after the first and last injections of daily cocaine, and those rats that showed >20% increase in motor activity after the last compared with the first injection were considered to have developed behavioral sensitization. The subjects that developed behavioral sensitization showed a significant increase in GluR1 levels in the nucleus accumbens at 3 weeks but not at 24 h of withdrawal. Conversely, sensitized animals showed a significant increase in NMDAR1 and GluR1 levels in the ventral tegmental area at 1 day but not at 3 weeks of withdrawal. None of these increases occurred in the rats exposed to daily cocaine that did not develop behavioral sensitization (<20% increase in motor activity), and no changes were measured in the level of GluR2/3 in any treatment group. The functional importance of the increases in glutamate receptor subunit levels is suggested by the fact that the changes were present only in rats that developed behavioral sensitization to repeated cocaine administration.

Dopamine depletion reorganizes projections from the nucleus accumbens and ventral pallidum that mediate opioid-induced motor activity

Motor activity elicited pharmacologically from the nucleus accumbens by the mu-opioid receptor agonist D-Ala-Tyr-Gly-NMePhe-Gly-OH (DAMGO) is augmented in rats sustaining dopamine depletions. GABAergic projections from the nucleus accumbens to ventral pallidum and ventral tegmental area (VTA) are involved because stimulation of GABAB receptors in the VTA (by baclofen) or GABAA receptors in the ventral pallidum (by muscimol) inhibit the motor response induced by the microinjection of DAMGO into the nucleus accumbens. The present study was done to determine which of these projections is mediating the augmented DAMGO-induced motor activity that follows 6-hydroxydopamine lesions of the nucleus accumbens. The inhibition of DAMGO-induced activation by pallidal injections of muscimol was markedly attenuated in lesioned animals, whereas the inhibition by VTA injections with baclofen was greatly enhanced. A similar switch in emphasis from pallidal to mesencephalic efferents was not observed for dopamine-induced motor activity, because muscimol microinjections inhibited the response elicited by dopamine microinjection into the nucleus accumbens in all subjects. The stimulation of mu-opioid receptors in the ventral pallidum also elicits motor activation, and this is blocked by baclofen microinjection into the VTA. However, after dopamine depletion in the nucleus accumbens, baclofen in the VTA was ineffective in blocking the motor response by DAMGO in the ventral pallidum. These data reveal that dopamine depletion in the nucleus accumbens produces a lesion-induced plasticity that alters the effect of mu-opioid receptor stimulation on efferent projections from the nucleus accumbens and ventral pallidum.

Antiinflammatory 2-benzyl-4-sulfonyl-4H-isoquinoline-1,3-diones: novel inhibitors of COX-2

A series of 2-benzyl-4-sulfonyl-4H-isoquinoline-1,3-diones was prepared. Members of this series are potent and selective inhibitors of cyclooxygenase-2 (COX-2) in both microsomal and cellular assays. Two representatives demonstrated activity in the carrageenan-induced paw edema model in rats upon oral administration.

Effect of structural modification of enol-carboxamide-type nonsteroidal antiinflammatory drugs on COX-2/COX-1 selectivity

Meloxicam (5), an NSAID in the enol-carboxamide class, was developed on the basis of its antiinflammatory activity and relative safety in animal models. In subsequent screening in microsomal assays using human COX-1 and COX-2, we discovered that it possessed a selectivity profile for COX-2 superior to piroxicam and other marketed NSAIDs. We therefore embarked on a study of enol-carboxamide type compounds to determine if COX-2 selectivity and potency could be dramatically improved by structural modification. Substitution at the 6- and 7-positions of the 4-oxo-1,2-benzothiazine-3-carboxamide, alteration of the N-methyl substituent, and amide modification were all examined. In addition we explored several related systems including the isomeric 3-oxo-1,2-benzothiazine-4-carboxamides, thienothiazines, indolothizines, benzothienothiazines, naphthothiazines, and 1,3- and 1,4-dioxoisoquinolines. While a few examples were found with greater potency in the COX-2 assay, no compound tested had a better COX-2/COX-1 selectivity profile than that of 5.

The ethics of providing intensive care in managed care organizations

To provide adequate and equitable care of critically ill patients, managed care organizations need to dedicate a reasoned proportion of organizational resources to the provision of critical care, distribute these resources fairly, establish appeal mechanisms, and monitor the outcomes of critical care. As in any healthcare delivery system with limited resources, it is inevitable that there will be limits to highly technological and costly life-sustaining care. Patients, physicians, and plan administrators will need to collaborate to decide priorities for care, since difficult trade-offs will need to be made between types of care and between quality and cost of care. The use of life-sustaining treatments should be informed by patient preferences and guided by many of the established guidelines for the provision of critical care. Physicians who provide critical care in a managed care organization should provide the most skilled and compassionate care to critically ill patients within the constraints of the ethically acceptable guidelines.

Expression of D1 receptor mRNA in projections from the forebrain to the ventral tegmental area

In situ hybridization was combined with Fluoro-Gold retrograde labeling to determine if cells projecting from the forebrain to the ventral tegmental area (VTA) express D1 receptor mRNA. Cell counts were made in the prefrontal cortex, shell of the nucleus accumbens, and ventral pallidum to estimate the percentage of neurons projecting to the VTA that express D1 receptor mRNA. Retrogradely labeled cells were observed in the infralimbic and prelimbic regions of the prefrontal cortex, and up to 37% of the retrogradely labeled cells expressed D1 receptor mRNA. Double-labeled cells constituted up to 89% of retrogradely labeled neurons in the rostral shell and up to 68% in the caudal shell of the nucleus accumbens. The number of retrogradely labeled cells in the ventral pallidum that were double-labeled ranged from 13% in the rostral to less than 10% in the caudal portions. These data provide anatomical support for a role of D1 receptors in the reciprocal innervation between the forebrain and VTA.

p53 immunoreactivity in non-melanoma skin cancer from immunosuppressed and immunocompetent individuals: a comparative study of 246 tumours

p53 immunoreactivity was examined in 132 cutaneous non-melanoma tumours from renal transplant recipients and in 114 histologically matched specimens from immunocompetent individuals. Skin lesions examined included 52 viral warts, 50 dysplastic keratoses, 51 intraepidermal carcinomas (IEC), 50 invasive squamous cell carcinomas (SCC) and 43 basal cell carcinomas (BCC). Overall, 51% (51/101) pre-malignant skin lesions and 45% (42/93) non-melanoma skin cancers (NMSC) showed p53 immunoreactivity, with extensive (> 50% cells positive) p53 staining in 27% (27/101) of pre-malignant and 20% (19/93) of malignant lesions. 17% (9/52) viral warts showed p53 immunoreactivity, but this was limited to focal or basal p53 staining. p53 immunoreactivity in all tumours was less in transplant than in non-transplant patients and this reached statistical significance for SCCs (p = 0.03).

Involvement of the ventral tegmental area in locomotion elicited from the nucleus accumbens or ventral pallidum

This study was designed to evaluate the role of the circuit containing the nucleus accumbens, ventral pallidum (VP) and ventral tegmental area (VTA) in the motor stimulation produced by the microinjection of dopamine, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or [D-Ala2, MePhe4,Gly-ol5]enkephalin (DAMGO) into VP or the shell and core compartments of the nucleus accumbens. Initial dose-response curves revealed that dopamine was approximately equipotent at producing motor activity after microinjection into the core and shell, AMPA was more effective in the core, whereas DAMGO was more potent in the shell. A role for the VTA in the motor responses elicited by dopamine, AMPA or DAMGO microinjection into the shell, core or VP was evaluated by microinjecting the tau-aminobutyric acidB agonist baclofen into the VTA to inhibit neuronal activity. Baclofen treatment abolished the motor responses elicited by AMPA from the shell, core and VP. The motor effect of DAMGO in the VP was abolished by baclofen, whereas the response in the shell was attenuated. The motor response to dopamine was unaltered by baclofen, regardless of the injection site. These data indicate that there exist differences between the core and shell of the nucleus accumbens in the capacity of neurotransmitter analogs to elicit motor activity, and that although AMPA-induced motor activity is dependent upon neurotransmission in the VTA after microinjection into the core, shell and VP, DAMGO-induced locomotion only requires such tone after microinjection into the VP and shell.

The mediodorsal nucleus of the thalamus in rats--I. forebrain gabaergic innervation

The aim of this study was to determine whether forebrain neurons projecting to the mediodorsal nucleus of the thalamus in rats express glutamate decarboxylase messenger RNA as a marker for GABAergic neurons. Forebrain glutamate decarboxylase messenger RNA-containing neurons that project to the mediodorsal nucleus were identified using a combination of retrograde tracing with Fluoro-Gold and in situ hybridization for the messenger RNA encoding the 67,000 molecular weight synthetic enzyme for GABA. Glutamate decarboxylase messenger RNA-containing afferents to the mediodorsal nucleus were observed in the olfactory tubercle, vertical limb of the diagonal band of Broca, ventral pallidum, sublenticular substantia innominata, globus pallidus, lateral preoptic area, bed nucleus of the stria terminalis and reticular nucleus of the thalamus. The largest proportions of glutamate decarboxylase messenger RNA-containing afferents to the mediodorsal nucleus were observed in the vertical limb of the diagonal band, ventral pallidal parts of the olfactory tubercle and the reticular nucleus of the thalamus. Somewhat fewer glutamate decarboxylase messenger RNA-containing, retrogradely labeled neurons were observed in the subcommissural ventral pallidum and sublenticular substantia innominata. These data suggest that a GABAergic projection from the basal forebrain to the mediodorsal nucleus of the thalamus can influence the function of this nucleus.

The mediodorsal nucleus of the thalamus in rats--II. Behavioral and neurochemical effects of GABA agonists

The aim of this study was to determine how GABA receptors in the mediodorsal nucleus of the thalamus in rats might contribute to the regulation of locomotor behavior. Microinjections of the GABAB and GABAA agonists, baclofen and muscimol, into the mediodorsal nucleus produced dose-dependent increases in locomotion that were blocked by co-administration of the GABAB antagonist, 2-hydroxysaclofen. Microinjection of baclofen along the midline, lateral into the ventrolateral thalamus or into the lateral ventricles produced significantly smaller dose-dependent increases in locomotion, indicating that the anatomical locus for baclofen-induced locomotion resides in the mediodorsal nucleus. The motor response elicited by microinjected baclofen was associated with a reduction in dopamine metabolism in the prefrontal cortex and an increase in metabolism in the core of the nucleus accumbens, but not in the accumbal shell or the dorsolateral striatum. These results suggest that GABAergic afferents to the mediodorsal nucleus may oppose a tonic inhibitory tone on locomotor activity. The data also suggest that the motor response produced by baclofen in the mediodorsal thalamus may arise by inhibiting the projections to the prefrontal cortex which modulate mesocorticolimbic dopamine transmission.

Substance P in the ventral pallidum: projection from the ventral striatum, and electrophysiological and behavioral consequences of pallidal substance P

The ventral pallidum of the basal forebrain contains a high concentration of substance P and receives a massive projection from the nucleus accumbens. The present study was designed to determine whether the accumbens serves as a source for substance P-containing fibers in the ventral pallidum and characterize the function of this tachykinin peptide within the ventral pallidum. By combining in situ hybridization for messenger RNA of the substance P prohormone, beta-preprotachykinin, with Fluoro-Gold retrograde labeling from iontophoretic deposits in the ventral pallidum, a population of substance P-containing neurons was demonstrated in the shell and core components of the nucleus accumbens and the ventromedial striatum. The function of substance P within the ventral pallidum was characterized at the level of the single neuron, and the behaving animal. Electrophysiological assessment revealed that approximately 40% of the 97 ventral pallidal neurons tested were readily excited by microiontophoretic applications of substance P or a metabolically stable agonist analog, DiMeC7 [(pGlu5, MePhe8, MeGly9)-substance P5-11]. Response characteristics were distinguished from glutamate-induced excitations by a slower onset and longer duration of action. Recording sites of tachykinin-sensitive neurons were demonstrated to be located throughout the ventral pallidum and within high densities of fibers exhibiting substance P-like immunoreactivity. When behaving rats received microinjections of DiMeC7 into this same region, the animals displayed an increase in motor activity, with a response threshold of 0.1nmol per hemisphere. These results verify the existence of a substantial substance P-containing projection from the nucleus accumbens to the ventral pallidum. The projection likely serves to excite ventral pallidal neurons for these neurons readily increased firing following local exposure to tachykinins. Furthermore, an increase in motor behavior appears to be a consequence of this neuronal response.

Dopamine depletion augments endogenous opioid-induced locomotion in the nucleus accumbens using both mu 1 and delta opioid receptors

The aim of this study is to analyze further the opioid receptor subtypes involved in the augmentation of behavioral activity after dopamine depletion in the nucleus accumbens of rats. Initially, the opioid receptors involved in the augmentation of locomotion produced by endogenous opioids were evaluated by microinjection of kelatorphan, an inhibitor of proteolytic enzymes that inactivates enkephalin, with or without specific antagonists for mu 1 or delta-opioid receptors, naloxonazine or naltrindole, respectively. Kelatorphan produced a dose-dependent increase in horizontal photocell counts and vertical movements. At all doses examined the behavioral response was augmented in rats sustaining accumbal dopamine lesions. The augmentation in dopamine-depleted rats was partially blocked by naloxonazine or naltrindole. Since the motor stimulant response to intra-accumbens microinjection of the delta-opioid agonist, [D-penicillamine2,5]-enkephalin, was not augmented in a previous study, we tested the behavioral response to a new endogenous delta-opioid agonist, [D-Ala2] deltorphin I. The locomotor response to deltorphin was slightly augmented in dopamine-depleted rats. These data suggest that the augmentation in the motor response elicited by endogenous opioids after dopamine lesions in the nucleus accumbens involves both mu 1, and delta-opioid receptors.

GABAergic projection from the ventral pallidum and globus pallidus to the subthalamic nucleus

There exists a topographically organized projection from the globus pallidus and ventral pallidum to the subthalamic nucleus and adjacent lateral hypothalamus. The participation of GABA as a neurotransmitter in this projection was evaluated by retrograde labeling of cells in the pallidal area from an iontophoretic deposit of Fluor-Gold in the subthalamus combined with in situ hybridization for mRNA of the GABA synthetic enzyme, glutamate decarboxylase (GAD). A rostrocaudal gradient in the contribution of GABA to the projection was demonstrated with a relatively small percentage of retrogradely labeled cells in the rostral ventral pallidum containing GAD mRNA (7%) compared to the caudal globus pallidus which had over 70% of the Fluoro-Gold containing cells double-labeled for GAD mRNA. Overall the ventral pallidum contribution to the subthalamic nucleus was less GABAergic than the portion arising from the globus pallidus (35% vs. 61%, respectively).

Atypical palatal ulceration

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A topographically organized gamma-aminobutyric acid projection from the ventral pallidum to the nucleus accumbens in the rat

Anatomical and electrophysiological studies have indicated that a reciprocal projection from the ventral pallidum back to the nucleus accumbens exists and has functional relevance. In this study, the topographical projection from the ventral pallidum to the nucleus accumbens was examined by using retrograde tracing with fluoro-gold iontophoresed in subcompartments of the nucleus accumbens in rats combined with either in situ hybridization for glutamic acid decarboxylase and preproenkephalin mRNA or substance P immunoreactivity. Deposits made into the medial nucleus accumbens preferentially labeled neurons in the medial ventral pallidum, while deposits into the dorsolateral nucleus accumbens, at or lateral to the anterior commissure, labeled primarily cells in the dorsal and lateral ventral pallidum. A mediolateral to rostrocaudal topography was also observed, with the medial deposits preferentially labeling cells in rostral ventral pallidum and the lateral deposits resulting in retrogradely labeled cells in the ventral pallidum below the crossing of the posterior anterior commissure (subcommissural) as well as below the globus pallidus (sublenticular). The majority of cells retrogradely labeled with fluoro-gold were double-labeled for glutamic acid decarboxylase mRNA. In contrast, very few retrogradely labeled neurons in the ventral pallidum were double labeled for mRNA for preproenkephalin. These data demonstrate a topographically organized projection from the ventral pallidum to the nucleus accumbens that is primarily gamma-aminobutyric acid (GABA)-ergic and reciprocal to the GABAergic projection from the nucleus accumbens to the ventral pallidum.

Sexual behavior, communication, and chlamydial infections among college women

The sexual practices, partner communication patterns, and prevalence of chlamydial infection were determined in a sample of college women. Specific inclusion criteria were used to screen 146 participants. The presence of a mucopurulent cervical discharge was the only criterion significantly associated with infection. Only 12% of the sample used condoms alone or in combination with another birth control method, and only 31% of the women discussed with their partner their own or their partner's sexual history. Thirty-eight percent of the sample reported a history of one to four episodes of a sexually transmitted disease, and 21% of the women stated they had had two or more sexual partners within the past 6 months. Health providers, counselors, and women themselves must address this health issue with more assertive behavior and communication skills.

Contribution of specific cell-adhesive glycoproteins to airway and alveolar inflammation and dysfunction

Using various animal models of toxic or antigenic-induced airway inflammation, we have demonstrated that adhesion molecules play an important role in the recruitment, retention, and site-specific activation of inflammatory cells within the airways. Furthermore, we have shown that cytokines may contribute to inflammatory responses in the airways by enhancing the expression of adhesion molecules on respiratory epithelial cells.

GABA and enkephalin projection from the nucleus accumbens and ventral pallidum to the ventral tegmental area

GABAergic and enkephalinergic afferents to the ventral tegmental area were investigated in the rat using retrograde tracing techniques combined with in situ hybridization. Following iontophoretic deposit of Fluoro-Gold in the ventral tegmental area labeling in the forebrain was most dense in the shell of the nucleus accumbens, rostral ventromedial ventral pallidum and diagonal band of Broca. A smaller density was also observed in the lateral septum. In these forebrain regions, the portion of retrogradely labeled cells that contained mRNA for glutamate decarboxylase ranged from 25% to 50%, whereas only 5% to 15% were double-labeled for preproenkephalin mRNA. Cells double-labeled with either glutamate decarboxylase or preproenkephalin mRNA were most numerous in the lateral septum, shell of the nucleus accumbens, rostral ventral pallidum and diagonal band of Broca. Large Fluoro-Gold deposits which invaded the medial substantia nigra resulted in a significant number of retrogradely labeled cells in the core of the nucleus accumbens, and a portion of these neurons also contained mRNA for glutamate decarboxylase or preproenkephalin. These data demonstrate the presence of GABAergic and enkephalinergic neurons projecting from the nucleus accumbens, ventral pallidum and diagonal band of Broca to the ventral tegmental area.

Keratin 17 expression as a marker for epithelial transformation in viral warts

The profile of keratin expression in benign warts from various cutaneous and mucosal sites along with dysplastic warts and squamous cell carcinomas has been examined using a panel of monospecific antibodies to epithelial keratins. Viral warts and verrucous keratoses from immunosuppressed renal transplant recipients show a spectrum of squamous atypia from benign lesions, from minimal changes to full thickness dysplasia. Changes associated with malignancy include loss of differentiation-specific keratins 1 and 10 together with expansion of basal cell epitopes and inappropriate expression of simple epithelial keratins 8, 18, and 19 in advanced squamous cell carcinoma. This late expression of keratins 8 and 18 contrasts with early expression of keratin 17 in all dysplastic lesions examined. Keratin 17 is found suprabasally in hyperproliferative lesions, including benign warts, but marked basal plus suprabasal expression is seen increasingly in malignantly transformed epidermis. These findings were not specific to immunosuppression, as shown by identical findings in control squamous cell carcinoma from nonimmunosuppressed individuals. Keratin 17 expression may prove prognostically helpful when assessing dysplasia in epidermal tumors.

Topography and functional role of dopaminergic projections from the ventral mesencephalic tegmentum to the ventral pallidum

A dopaminergic projection from the ventral tegmental area to the ventral pallidum was identified in the rat using anterograde tract tracing and combined retrograde tracing-immunocytochemistry. The projection was found to be topographically organized such that fibers innervating the ventromedial ventral pallidum arose from neurons located along the midline nuclei of the ventral mesencephalon, including the nucleus interfascicularis and nucleus linearis caudalis. Ventral tegmental neurons situated more laterally, in the nucleus parabrachialis pigmentosus and nucleus paranigralis, projected to the ventromedial and dorsolateral ventral pallidum. The substantia nigra did not supply a major contribution to this projection. The proportion of ventral tegmental area dopaminergic neurons projecting to the ventral pallidum ranged from approximately 30% to 60%. The functional significance of the projection is indicated since intra-ventral pallidum microinjections of dopamine elicited a dose-dependent increase in locomotor activity. Furthermore, whereas pretreatment of the ventral pallidum with the GABAA agonist muscimol has been shown to attenuate opioid-induced locomotor activity elicited from the ventral pallidum, it did not attenuate the dopamine-induced motor response. Thus, while mu-opioids in the ventral pallidum may presynaptically regulate GABAergic efferents from the nucleus accumbens, it appears that the dopaminergic input directly influences the ventral pallidal output neuron which is involved in locomotion.

Patterns of glucose use after bicuculline-induced convulsions in relationship to gamma-aminobutyric acid and mu-opioid receptors in the ventral pallidum--functional markers for the ventral pallidum

Bicuculline-induced convulsions increased glucose use throughout the brain and sharply demarcated the ventral pallidum and globus pallidus. Glucose use in the nucleus accumbens also increased after bicuculline-induced convulsions, except for a circumscribed region in the dorsomedial shell. Since the projection from the nucleus accumbens to the ventral pallidum contains gamma-aminobutyric acid (GABA) and the opioid peptide, enkephalin, the pattern of increased glucose use in the ventral pallidum and nucleus accumbens after bicuculline-induced convulsions was compared to the topography of GABAA and mu-opioid receptors. The pattern of glucose use in the nucleus accumbens and ventral pallidum resembled the topography of GABAA, but differed from that of mu-opioid receptors. Bicuculline may disinhibit GABAergic efferents to the ventral pallidum resulting in a dramatic increase in glucose use within striatopallidal synaptic terminals as well as in local terminals of the pallidal projection neurons.

Dopamine depletion produces augmented behavioral responses to a mu-, but not a delta-opioid receptor agonist in the nucleus accumbens: lack of a role for receptor upregulation

Microinjection of either mu- or delta-opioid agonists into the nucleus accumbens produces an increased locomotor activity, and when the dopaminergic innervation of the nucleus accumbens is bilaterally lesioned, the locomotor response to the microinjection of mixed mu- and delta-opioid agonists is augmented. To determine whether the lesion-induced augmentation to opioids is specific to mu- or delta-opioid receptor activation, dopamine innervation of the nucleus accumbens was lesioned with 6-hydroxydopamine (6-OHDA), and the motor stimulant response to intra-accumbens microinjection of the selective mu-opioid agonist, Tyr-D-Ala-Gly-mePhe-Gly-OH (DAMGO), was compared to that of the delta-opioid agonist, [D-penicillamine2,5]-enkephalin (DPDPE). The lesions caused a 95% depletion of tissue dopamine levels in the nucleus accumbens of the DAMGO-injected rats compared to sham-lesioned rats. Horizontal and vertical photocell counts were significantly increased in response to DAMGO in 6-OHDA-lesioned compared to the sham-lesioned rats. This behavioral augmentation was dose dependent and blocked by naloxone. In rats with similar accumbal dopamine depletions (94%), the locomotor response to DPDPE was not enhanced. The augmentation in the behavioral response to DAMGO was not associated with a change in the Bmax or Kd of [125I]DAMGO binding in nucleus accumbens homogenates from lesioned rats. Likewise, using quantitative receptor autoradiography, no difference between 6-OHDA- and sham-lesioned rats was observed in [125I]DAMGO or [125I]DPDPE binding. Therefore, the augmented behavioral response to opioids in the nucleus accumbens following dopamine depletion relies predominately on mu-opioid receptor stimulation. However, this augmentation is not mediated by an alteration in the number or affinity of these receptors.

Dopamine and endogenous opioid regulation of picrotoxin-induced locomotion in the ventral pallidum after dopamine depletion in the nucleus accumbens

Microinjection of picrotoxin or the mu-opioid agonist, Tyr-D-Ala-Gly-NmePhe-Gly-OH (DAMGO), into the ventral pallidum (VP) produces an increase in locomotor activity that is antagonized by dopamine receptor blockade. To investigate the regulation of VP-induced locomotion by the dopaminergic innervation of the nucleus accumbens (NA) and the role of opioid receptors in this regulation, dopamine innervation of the NA was bilaterally lesioned with 6-hydroxydopamine (6-OHDA). The lesions resulted in an 89-97% depletion of tissue dopamine levels in the nucleus accumbens compared with sham-lesioned rats. Dopamine depletion in the NA failed to significantly antagonize picrotoxin or DAMGO injected into the VP. However, the dopamine receptor antagonist, haloperidol (0.1 mg/kg, IP), blocked the picrotoxin-initiated increase in horizontal photocell counts in both sham- and 6-OHDA-lesioned rats. The opioid receptor antagonist, naloxone (1.0 mg/kg, SC), also blocked the picrotoxin-induced locomotion in 6-OHDA-lesioned rats but did not block locomotion in the sham-lesioned rats. At a higher dose (3.0 mg/kg, SC), naloxone blocked picrotoxin-induced locomotion in both sham- and 6-OHDA-lesioned rats. These results indicate that although dopamine depletion in the NA does not affect the permissive role of dopamine transmission on locomotion elicited from the VP, it results in an increased sensitivity to enkephalinergic transmission.

Autoradiographic localization of gamma-aminobutyric acidA receptors within the ventral tegmental area

Destruction of intrinsic neurons in the ventral tegmental area (VTA) with the excitotoxin, quinolinic acid produced a significant decrease (80%) in [3H]muscimol binding to GABAA receptors within the parabrachial pigmented and paranigral nuclei of the VTA. Selective destruction of the dopaminergic neurons with 6-hydroxydopamine (6-OHDA) did not reduce [3H]muscimol binding within the VTA. However, the destruction of dopaminergic neurons did produce an increase (20%) in [3H]muscimol binding contralateral to the lesion, suggesting a reduction in the GABAergic innervation to this region. Additionally, destruction of the VTA afferents with quinolinic acid injections in the medial accumbens failed to produce alterations in [3H]muscimol binding within the VTA. These results are consistent with the predominant localization of GABAA receptors to non-dopaminergic neurons intrinsic to the VTA.

GABAA receptors in auditory brainstem nuclei of the chick during development and after cochlea removal

The presence of GABAA receptors (GABARs) in auditory brainstem nuclei of the chick was determined by immunocytochemical (ICC) and receptor autoradiographic techniques. A monoclonal antibody to the GABAR/benzodiazepine/chloride channel complex and radiolabeled ligand binding using [3H]-muscimol, a GABA agonist, revealed labeling in nucleus magnocellularis (NM), nucleus laminaris (NL), nucleus angularis (NA), and the superior olive (SO) in both posthatch and embryonic chicks. GABAR-immunoreactivity (GABAR-I), as well as [3H]-muscimol binding, appear homogeneous throughout these nuclei at all ages studied. During development, GABAR-I is first observed in these nuclei around embryonic day 13 (E13). GABAR-I, which appears heavier in embryos than in posthatch chicks, becomes less intense with age in all 4 nuclei. Levels of receptor binding are also greater in embryos compared to posthatch chicks. [3H]-Muscimol binding is consistently greatest in SO followed by that in NL. NM and NA exhibit the least amount of binding at all ages studied. [3H]-Muscimol binding decreases in auditory brainstem nuclei as a function of age. Two days after unilateral cochlea removal, there is an apparent increase in GABAR-I in the ipsilateral NM compared to controls. This, however, may be the result of a decrease in the cross-sectional area of NM neurons as a result of de-afferentation (Born and Rubel, 1985). In contrast, there is a 28% decrease in [3H]-muscimol binding in the ipsilateral NM compared to controls probably reflecting the 30% reduction in the number of NM neurons due to cochlea removal (Born and Rubel, 1985). Fourteen days after cochlea removal, there is still a small, but not significant, decrease in [3H]-muscimol binding in the ipsilateral NM. In the contralateral NM, GABAR-I is less intense compared to that in the ipsilateral NM and controls. Additionally, there is a slight but insignificant decrease in [3H]-muscimol binding compared to that in controls 2 days after cochlea removal. After 14 days survival, however, the average binding is similar to that in controls. Thus, cochlea removal appears to transiently decrease the number of GABARs in the ipsilateral NM and may have a similar, but not as dramatic, effect in the contralateral NM. These GABARs are most likely to be postsynaptic, that is, located on NM neurons.

Interaction of platelet-activating factor with cultured guinea pig tracheal epithelial cells

The present study has examined the interaction of platelet-activating factor (PAF) with cultured guinea pig tracheal epithelial cells (GTE). PAF stimulated GTE to release endogenous arachidonic acid and metabolize it to prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha). Prostanoid production by GTE in response to PAF was dose-dependent (0.1-100 nM) and was maximal within 5 min. PGE2 and PGF2 alpha levels increased by 3.3 +/- 0.8 and 3.2 +/- 0.6 ng/10(6) cells respectively over basal levels in response to 100 nM-PAF. The ability of GTE to synthesize and/or catabolize PAF was also examined. GTE readily incorporated [3H]acetate into a product which migrated on t.l.c. with PAF. However, further characterization of this product suggested that label had not been incorporated into PAF, but rather that it was incorporated into another lipid product with chromatographic characteristics similar to those of PAF. In contrast, GTE readily metabolized PAF to inactive products. When [3H]PAF was incubated with GTE, 50% of the total [3H]PAF added was catabolized in approx. 15 min. The major route of catabolism of PAF by GTE was the deacetylation-reacylation pathway, which yielded 1-O-[3H]alkyl-2-acyl-sn-glycerophosphocholine. Determination of the nature of the long-chain acyl group incorporated into the sn-2 position of the newly synthesized products revealed that oleic and linoleic acids were the major fatty acids present. Taken together, these results suggest that respiratory epithelial cells respond to stimulation by PAF with enhanced production of PGE2 and PGF2 alpha, and also have the capacity to modulate inflammatory reactions in the airways by their ability to degrade this potent inflammatory mediator.

GABAA receptors containing alpha 1 and beta 2 subunits are mainly localized on neurons in the ventral pallidum

The gamma-aminobutyric acid (GABA) projection from the nucleus accumbens to the ventral pallidum (VP) is important in the regulation of locomotion. Thus, stimulation and inhibition of GABAA receptors in the VP can alter locomotor activity. To determine whether the GABAA receptors are located presynaptically on accumbens efferents to the VP or postsynaptically on neurons intrinsic to the VP two experiments were performed. In the first, quinolinic acid lesions of the nucleus accumbens did not alter [3H]muscimol binding in the VP, while lesions in the VP significantly reduced (60-80%) binding as measured by light microscopic receptor autoradiography. In the second experiment, in situ hybridization with oligonucleotide probes for mRNAs of the alpha 1 and beta 2 subunits of the GABAA receptor was examined in the nucleus accumbens and VP. No mRNA for either subunit was observed in the nucleus accumbens, although many positively labeled neurons were present within the VP. By contrast, a moderate to high density of cells in both the nucleus accumbens and VP contained mRNA for glutamic acid decarboxylase. These data argue that the majority of GABAA receptors in the VP are not located presynaptically on axonal terminals originating from neurons in the nucleus accumbens.

gamma-Aminobutyric acid and mu-opioid receptor localization and adaptation in the basal forebrain

In conclusion, GABAA receptors containing the alpha 1 subunit are localized on postsynaptic neurons in the ventral pallidum, mainly in the dorsolateral compartment and on presynaptic terminals in the nucleus accumbens. mu-opioid receptors are localized on postsynaptic neurons in both the nucleus accumbens and ventral pallidum, and therefore may be regulating presynaptic release of enkephalin from the accumbens-pallidal projection. Discrete lesions in the dorsomedial core of the nucleus accumbens will upregulate GABAA receptors in the dorsolateral compartment of the nucleus accumbens in a fashion similar to the upregulation of GABAA receptors in the globus pallidus after striatal lesions. However, larger lesions of the lateral core projection to the dorsolateral compartment of the ventral pallidum do not upregulate the GABAA receptors, suggesting that the mechanisms for upregulation of GABAA receptors are specific to the dorsomedial core or a smaller lesion. The uniqueness of the compartments within the nucleus accumbens and the ventral pallidum are supported by these receptor and mRNA analyses.

Pharmacology of nasal provocation with bradykinin: studies of tachyphylaxis, cyclooxygenase inhibition, alpha-adrenergic stimulation, and receptor subtype

We have evaluated mechanisms by which nasal provocation with bradykinin may induce symptoms of rhinitis. Repeated nasal challenges with 100 micrograms of bradykinin led to reproducible increases in symptoms and in vascular permeability. Premedication with aspirin did not alter bradykinin-induced responses. Topical application of the alpha-adrenergic agonist oxymetazoline significantly reduced bradykinin-induced subjective nasal congestion scores, but did not lead to a significant decrease in total symptoms or in vascular permeability. Finally, the B1 kinin receptor agonist des-Arg9-bradykinin (1 mg) was totally ineffective in inducing symptoms or increasing vascular permeability. Thus, nasal provocation with bradykinin leads to induction of symptoms and increased vascular permeability, presumably via stimulation of B2 kinin receptors, and is not dependent on prostanoid generation.

Specificity in the projection patterns of accumbal core and shell in the rat

The efferent projections of the core and shell areas of the nucleus accumbens were studied with a combination of anterograde and retrograde tract-tracing methods, including Phaseolus vulgaris-leucoagglutinin, horseradish peroxidase and fluorescent tracers. Both the core and shell regions project to pallidal areas, i.e. ventral pallidum and entopeduncular nucleus, with a distinct topography in the sense that the core projection is located in the dorsolateral part of ventral pallidum, whereas the shell projects to the medial part of the subcommissural ventral pallidum. Both regions of the accumbens also project to mesencephalon with a bias for the core projection to innervate the substantia nigra-lateral mesencephalic tegmentum, and for the shell projection to reach primarily the ventral tegmental-paramedian tegmentum area. The most pronounced differences between core and shell projections exist in regard to the hypothalamus and extended amygdala. Whereas the core projects primarily to the entopeduncular nucleus including a part that invades the lateral hypothalamus, the shell, in addition, projects diffusely throughout the rostrocaudal extent of the lateral hypothalamus as well as to the extended amygdala, especially its sublenticular part. Both the core and shell of the accumbens have unmistakable striatal characteristics both histologically and in their connectional patterns. The shell, however, has additional features that are reminiscent of the recently described extended amygdala [Alheid G.F. and Heimer L. (1988) Neuroscience 27, 1-39; de Olmos J.S. et al. (1985) In The Rat Nervous System, pp. 223-334]; in fact, the possibility exists that the shell represents a transitional zone that seems to characterize most of the fringes of the striatal complex, where it adjoins the extended amygdala.

Changes in gamma-aminobutyric acid, mu-opioid and neurotensin receptors in the accumbens-pallidal projection after discrete quinolinic acid lesions in the nucleus accumbens

Discrete quinolinic acid lesions in the nucleus accumbens altered [3H]muscimol binding to gamma-aminobutyric acid receptors, [125I]neurotensin binding to neurotensin receptors, [125I]Tyr-D-Ala-Gly-NMePHe-Gly-OH binding to mu-opioid receptors, and [3H]quinuclidinyl benzilate binding to muscarinic receptors. Within lesions of the lateral accumbens core, [3H]muscimol binding increased and [125I]Tyr-D-Ala-Gly-NMePhe-Gly-OH, [125I]neurotensin and [3H]quinuclidinyl benzilate binding decreased. Lesions of the medial nucleus accumbens resulted in decreased [125I]Tyr-D-Ala-Gly-NMePhe-Gly-OH and [3H]quinuclidinyl benzilate binding while no alterations were observed for [3H]muscimol or [125I]neurotensin binding. These data support anatomical distinctions between medial and lateral nucleus accumbens. Destruction of intrinsic neurons in the dorsomedial nucleus accumbens core increased [3H]muscimol binding in the dorsal rim of the ventral pallidum and the rostral globus pallidus without altering [125I]Tyr-D-Ala-Gly-NMePhe-Gly-OH binding. Destruction of neurons in the lateral nucleus accumbens core or medial shell did not alter [3H]muscimol binding in the ventral pallidum. The lack of upregulation in gamma-aminobutyric acid receptors suggests that the gamma-aminobutyric acid-containing projection from the dorsomedial core to the dorsal rim of the ventral pallidum differs from the projection from the lateral accumbens core and medial shell to the more ventral regions of the pallidum. Fluoro-gold retrograde tracer histochemistry confirmed the specific projection from the dorsomedial core to the dorsal ventral pallidum; and from the shell of the nucleus accumbens to more ventral regions of the ventral pallidum.