Cost of care and its impact on households due to lymphatic filariasis: Analysis of a national sample survey in India.

BACKGROUND AND OBJECTIVES: India is an endemic country for lymphatic filariasis (LF). There are no current estimates of the expenditure being borne by LF patients in case of outpatient care or hospitalisation and its impact on households. This study aimed to estimate the household out-of-pocket (OOP) expenditure due to hospitalization or outpatient care as a result of LF in India. METHODS: Secondary analysis of nationally representative data for India collected by the National Sample Survey Organization in 2014 was performed, reporting on health service utilization and health care related OOP expenditure by income quintiles and by type of health facility (public or private). RESULTS: The median household OOP expenditure from hospitalization and outpatient care due to LF was US$ 178 and US$ 04, respectively; and was more than two times higher among the richest group compared to the poorest. There was a significantly higher proportion of households affected by catastrophic costs among the rich (30%) compared to the poor households (18%) due to hospitalization. Median private sector OOP hospitalization expenditure was nearly four times higher than the public sector. Less than one-fourth of outpatient visits (22%) were in the public sector. The median expenditure on medicines and indirect cost were US$ 32 (IQR: 17-84) and US$ 23 (IQR: 9-59), respectively in case of hospitalization due to LF; while in case of outpatient care these were US$ 1.5 (IQR: 0-5.8) and US$ 1.5 (IQR: 0-4), respectively. INTERPRETATION & CONCLUSION: Households with LF incur huge cost of patient care, particularly those in the lowest income group and those seeking care in the private sector.

Cost of injury care in India: cross-sectional analysis of National Sample Survey 2014.

BACKGROUND: Injuries account for nearly 10% of total deaths in India and this burden is likely to rise. We aimed to estimate the out-of-pocket (OOP) expenditure and catastrophic expenditure due to hospitalisation or outpatient care as a result of any injury and factors associated with incurring catastrophic expenditure. METHODS: Secondary analysis of nationally representative data for India collected by National Sample Survey Organization in 2014, reporting on health service utilisation and healthcare-related OOP expenditure by income quintiles and by type of health facility (public or private). RESULTS: The median expenditure per episode of hospitalisation due to any injury was US$156, and it was three times higher among the richest quintile compared with the poorest quintile (p<0.001). There was a significantly higher prevalence (p<0.001) of catastrophic expenditure among the poorest quintile (32%) compared with the richest (21%). Mean private sector OOP hospitalisation expenditure was five times higher than in the public sector (p<0.001). Medicines accounted for 37% and 58% of public sector hospitalisation and outpatient care, respectively. Patients treated in a private facility, hospitalised for over 7 days, in the poorest wealth quintiles and of general caste had higher odds of incurring catastrophic expenditure. CONCLUSION: People who sustain an injury have a high risk of catastrophic household expenditure, particularly for those in lowest income quartiles. There is a clear need for publicly funded risk protection mechanisms targeting the poor. Promotion of generic medicines and subsidisation for the poorest wealth quintile may also reduce OOP expenditure in public sector facilities.

Cost of hospitalisation for non-communicable diseases in India: are we pro-poor?

OBJECTIVES: To estimate out-of-pocket (OOP) expenditure due to hospitalisation from NCDs and its impact on households in India. METHODS: The study analysed nationwide representative data collected by the National Sample Survey Organisation in 2014 that reported health service utilisation and healthcare-related OOP expenditure by income quintiles and by type of health facility (public or private). The recall period for inpatient hospitalisation expenditure was 365 days. Consumption expenditure was collected for a recall period of 1 month. OOP expenditure amounting to >10% of annual consumption expenditure was termed as catastrophic. Weighted analysis was performed. RESULTS: The median expenditure per episode of hospitalisation due to NCDs was USD 149 - this was ~3 times higher among the richest quintile compared to poorest quintile. There was a significantly higher prevalence of catastrophic expenditure among the poorest quintile, more so for cancers (85%), psychiatric and neurological disorders (63%) and injuries (63%). Mean private-sector OOP hospitalisation expenditure was nearly five times higher than that in the public sector. Medicines accounted for 40% and 27% of public- and private-sector OOP hospitalisation expenditure, respectively. CONCLUSION: Strengthening of public health facilities is required at community level for the prevention, control and management of NCDs. Promotion of generic medicines, better availability of essential drugs and possible subsidisation for the poorest quintile will be measures to consider to reduce OOP expenditure in public-sector facilities.

The effect of ibuprofen on bleeding during periodontal surgery.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used medications for both medical and dental ailments. These drugs have been shown to increase bleeding during surgeries, which may prompt practitioners to discontinue their use before surgical procedures. The aim of the present study is to assess the effect of a common NSAID, ibuprofen, on bleeding during periodontal surgery. MATERIALS AND METHODS: The study group consisted of 10 patients who were scheduled to undergo periodontal surgery of similar type, complexity, and duration. Each subject acted as control as well as case group. The case group consisted of 10 surgeries in which patients were administered ibuprofen prior to surgery, whereas ibuprofen was not administered in control group. Bleeding time was measured at first visit and prior to first and second surgeries. The volume of blood loss during each surgery was measured by subtracting the amount of water used for irrigation from the total volume of fluid collected in the portable aspirator at the end of the surgery. RESULTS: The result showed a statistically significant (P < 0.05) increase in intraoperative bleeding during periodontal surgery when ibuprofen was preadministered. In addition, there was statistically significant (P < 0.05) increase in bleeding time. CONCLUSION: Ibuprofen taken prior to periodontal surgery increases intraoperative bleeding and should be administered cautiously before periodontal surgeries.

Cost of diabetic care in India: An inequitable picture.

AIM: Diabetes is a growing public health problem in India which is soon going to become the 'diabetes capital' of the world. It requires regular care and follow up. We aimed to estimate the household out-of-pocket (OOP) expenditure and catastrophic expenditure due to hospitalization and outpatient care as a result of diabetes. MATERIALS AND METHODS: Secondary analysis of nationally representative data for India collected by National Sample Survey Organization in 2014, reporting on health service utilization and health care related OOP expenditure by income quintiles and by type of health facility (public or private). RESULTS: The median household OOP expenditure from hospitalization due to diabetes was USD 151, and was 3 times higher among the richest quintile compared to the poorest quintile (p<0.001). There was a significantly higher prevalence (p<0.001) of catastrophic expenditure among the poorest quintile (36%) compared to the richest (14%). Median private sector OOP hospitalization expenditure was four times higher than the public sector (p<0.001). Medicines accounted for 41% and 69% of public sector hospitalization and outpatient care respectively. Concentration indices show gross inequity in hospitalization expenditure, prevalence of catastrophic expenditure and utilization of public health facility. CONCLUSION: Households with diabetic patients incur a high risk of catastrophic expenditure, particularly for those in the lowest income quintiles and those seeking care in the private sector. Increased availability and access to essential drugs and strengthening of public facilities will significantly reduce OOP expenditure.

Data collection using open access technology in multicentre operational research involving patient interviews.

Conducting multicentre operational research is challenging due to issues related to the logistics of travel, training, supervision, monitoring and troubleshooting support. This is even more burdensome in resource-constrained settings and if the research includes patient interviews. In this article, we describe an innovative model that uses open access tools such as Dropbox, TeamViewer and CamScanner for efficient, quality-assured data collection in an ongoing multicentre operational research study involving record review and patient interviews. The tools used for data collection have been shared for adaptation and use by other researchers.

Conduire des recherches opérationnelles multicentriques est un défi, particulièrement dans les contextes de ressources limitées, en tenant compte des questions de logistique de déplacement, de formation, de supervision, de suivi et de soutien à la résolution des problèmes; encore plus si cette recherche implique des entretiens avec des patients. Dans cet article, nous décrivons un modèle innovant qui utilise des outils à accès ouvert comme Dropbox, TeamViewer et CamScanner pour un recueil de données efficace et de qualité assurée dans le cadre d'une recherche opérationnelle continue multicentrique impliquant des revues de dossiers et des entretiens avec des patients. Les outils utilisés pour le recueil de données ont été partagés pour l'adaptation et l'utilisation par d'autres chercheurs.

La realización de investigaciones operativas multicéntricas puede ser problemática, sobre todo en los entornos con restricción de los recursos, habida cuenta de las dificultades en la organización de los desplazamientos, la capacitación, la supervisión, el seguimiento y el apoyo a la resolución de problemas; más aun, cuando la investigación precisa entrevistas a los pacientes. En el presente artículo se describe un modelo innovador que utiliza herramientas de libre acceso como las plataformas Dropbox, TeamViewer y CamScanner, con el fin de lograr una obtención de datos eficiente y de calidad garantizada, en una investigación operativa multicéntrica en curso que comporta el examen de las historias clínicas y entrevistas a los pacientes. Se comunican las herramientas utilizadas en la recogida de datos, con la finalidad de que otros investigadores puedan adaptarlas y las apliquen.

Experience of active tuberculosis case finding in nearly 5 million households in India.

In India, to increase tuberculosis (TB) case detection under the National Tuberculosis Programme, active case finding (ACF) was implemented by the Global Fund-supported Project Axshya, among high-risk groups in 300 districts. Between April 2013 and December 2014, 4.9 million households covering ~20 million people were visited. Of 350 047 presumptive pulmonary TB cases (cough of ⩾2 weeks) identified, 187 586 (54%) underwent sputum smear examination and 14 447 (8%) were found to be smear-positive. ACF resulted in the detection of a large number of persons with presumptive pulmonary TB and smear-positive TB. Ensuring sputum examination of all those with presumptive TB was a major challenge.

En Inde, le projet Axshya (soutenu par le Fonds Mondial) a mis en œuvre une recherche active des cas (ACF) afin d'en augmenter la détection sous l'égide du Programme Révisé National Contre la Tuberculose auprès des groupes à risque dans 300 districts. Entre avril 2013 et décembre 2014, 4,9 millions de foyers, soit environ 20 millions de personnes, ont été visités. De 350 047 cas présumés de tuberculose (TB) pulmonaire (toux ⩾2 semaines) identifiés, 187 586 (54%) ont bénéficié d'un examen de frottis de crachats et 14 447 (8%) ont eu un frottis positif. L'ACF a abouti à la détection d'un grand nombre de personnes présumées atteintes de TB pulmonaire et de TB à frottis positif. Assurer l'examen des crachats de tous les cas avec suspicion de TB a été un défi majeur.

Con el propósito de aumentar la detección de casos en la India, el Proyecto Axshya (financiado por el Fondo Mundial) introdujo un mecanismo de búsqueda activa de casos (ACF), dirigido a los grupos de alto riesgo en 300 distritos, en el marco del Programa Nacional Revisado Contra la Tuberculosis. De abril del 2013 a diciembre del 2014 se visitaron 4,9 millones de hogares, que cubrían una población cercana a 20 millones de personas. Se detectaron 350 047 casos con presunción de tuberculosis (TB) pulmonar (tos con una duración de ⩾2 semanas), se practicó la baciloscopia del esputo a 187 586 personas (54%), de las cuales 14 447 obtuvieron un resultado positivo (8%). La ACF dio lugar a la detección de un gran número de personas con presunción de TB pulmonar y baciloscopia positiva del esputo. La realización del examen microscópico del esputo en todas estas personas representó un gran desafío.

The dopamine transporter in mesencephalic cultures is refractory to physiological changes in membrane voltage.

The dopamine transporter (DAT) plays a crucial role in the clearance of extracellular dopamine in brain. Uptake of dopamine by the cloned human DAT has been shown to be electrogenic and voltage-dependent, with greater uptake observed at hyperpolarized potentials. Ventral mesencephalic dopaminergic neurons were used to assess the kinetics of dopamine uptake in relation to their electrical activity. Dopamine uptake in these cultures was saturable with a K(m) of approximately 560 +/- 60 nm and a DAT turnover rate of 0.74 +/- 0.07 dopamine molecules per second. The effects of physiological changes in membrane voltage on transporter function were assessed by the activation of G-protein-coupled receptors. Current-clamp recordings of dopamine neurons showed that dopamine, baclofen, and orphanin FQ (OFQ) cause varying degrees of hyperpolarization. However, dopamine uptake was not affected by the activation of D(2), GABA(B), or OFQ receptors. Dopamine neurons in culture fired spontaneous action potentials at an average frequency of 2.3 Hz. Thus, dopamine neurons fire approximately three action potentials in the time taken for DAT to go through one transport cycle. Application of tetrodotoxin (1 microm) blocked action potentials but did not alter the uptake of dopamine. These data demonstrate that DAT turnover is a relatively slow process and the rate-limiting step for transport cycle is insensitive to changes in membrane voltage in physiological range.

Neurotrophin-3 contributes to the initiation of behavioral sensitization to cocaine by activating the Ras/Mitogen-activated protein kinase signal transduction cascade.

These experiments were designed to assess the role of neurotrophins and the Ras/mitogen-activated protein kinase (MAP) signal transduction cascade in behavioral sensitization to cocaine. The first experiments evaluated the effect of three daily intra-ventral tegmental area (VTA) microinjections of neurotrophin-3 (NT-3) or brain-derived neurotrophic factor (BDNF) on the behavioral-activating effects of a subsequent challenge injection of cocaine in rats. Results indicated that, although NT-3 did not influence behavior across the three microinjection days, animals displayed a sensitized behavioral response to the subsequent cocaine challenge injection. In contrast, BDNF microinjections resulted in a progressive increase in behavioral activity but did not influence the subsequent behavioral response to cocaine. A second series of experiments assessed the effect of inhibiting the MAP kinase signal transduction cascade on the initiation of behavioral sensitization to cocaine. The MAP kinase kinase inhibitor PD98059, or its vehicle, was microinjected into the VTA before three daily cocaine injections. Although PD98059 did not influence the acute behavioral response to cocaine, it blocked sensitization. Finally, the effects of acute and repeated cocaine injections on NT-3 and BDNF mRNA levels in the VTA, substantia nigra, and hippocampus were assessed. Results indicated that an acute cocaine injection resulted in a transient increase in NT-3 mRNA levels in the VTA. Collectively, these results suggest that NT-3 contributes to the initiation of behavioral sensitization to cocaine by activating the Ras/MAP kinase signal transduction system. The present data also indicate that BDNF itself produced a progressive augmentation in behavioral activation with repeated administration.

Expression of cocaine sensitization: regulation by the medial prefrontal cortex.

Extracellular levels of dopamine are increased in response to systemic administration of cocaine in several brain areas including the nucleus accumbens and medial prefrontal cortex. While the cocaine-induced increase in extracellular dopamine levels in the nucleus accumbens is augmented after repeated daily cocaine, the response of extracellular dopamine levels in the medial prefrontal cortex is attenuated. Since dopamine in the medial prefrontal cortex has an inhibitory effect on nucleus accumbens dopamine levels and locomotor activity, the role of medial prefrontal cortex dopamine tolerance in the expression of sensitized locomotor behavior was further examined by injection of D-amphetamine sulfate into the prelimbic portion of the medial prefrontal cortex just prior to cocaine challenge in cocaine-sensitized rats. Male Sprague-Dawley rats were non-handled (naive) or injected with either saline (1 ml/kg, i.p.) or cocaine (15 mg/kg, i.p.) for five consecutive days. After a seven to 12 day withdrawal period, rats were microinjected with either saline or various doses of amphetamine into primarily the prelimbic region of the medial prefrontal cortex followed by systemic injection of saline or cocaine. In naive rats, intramedial prefrontal cortex amphetamine produced a trend toward decreased locomotor responding to cocaine challenge while no effect of amphetamine was evident in daily saline pretreated rats. Daily cocaine pretreated rats that received saline in the medial prefrontal cortex demonstrated a sensitized locomotor response compared to their daily saline pretreated counterparts. This sensitization was blocked by a low dose of amphetamine (0.175 microg/side) in the medial prefrontal cortex, an effect which disappeared in animals administered higher amphetamine doses. The results suggest that in rats sensitized to cocaine, decreased medial prefrontal cortex dopamine levels in response to cocaine challenge may contribute to behavioral sensitization. Furthermore, the data indicate the possibility that there is an optimal range at which medial prefrontal cortex amphetamine exerts maximal behavioral inhibition. These findings implicate a role for decreased cortical control in producing sensitized behavioral responding to cocaine.

Potential role of stress and sensitization in the development and expression of multiple chemical sensitivity.

Chemical sensitivity in humans may be an acquired disorder in which individuals become increasingly sensitive to chemicals in the environment. It is hypothesized that in individuals with multiple chemical sensitivity (MCS), a sensitization process has occurred that is akin to behavioral sensitization and kindling observed in rodents. In the rodent sensitization model, repeated exposure to stress or drugs of abuse enhances behavioral and neurochemical responses to subsequent stimuli (stress or drugs of abuse). Kindling is a form of sensitization in which repeated application of electrical stimuli applied to the brain at low levels culminates in the induction of full-blown seizures when the same stimulus is applied at a later time. A similar sensitization of specific limbic pathways in the brain may occur in individuals with MCS. The time-dependent nature of sensitization and kindling and the role of stress in the development of sensitization are discussed in the context of rodent models, with an emphasis on application of these models to human studies of MCS.

Stress-induced cross-sensitization to cocaine: effect of adrenalectomy and corticosterone after short- and long-term withdrawal.

We have recently shown that adrenalectomy (ADX) in rats blocks the appearance of cocaine-induced sensitization when this behavioral response is tested at early withdrawal times (1-2 days), but not after later withdrawal from cocaine (12 days). To determine if a similar phenomenon occurred with stress-induced sensitization, male Sprague-Dawley rats were given a sham ADX, ADX surgery, or ADX plus s.c. implanted corticosterone (CORT) pellets (CORT 12.5% pellets or CORT 50% pellets). A fifth group was given ADX surgery, but CORT 50% pellets were implanted after repeated stress treatment. One week after surgery, each group was divided into two additional groups, naive and stress. Naive animals remained unhandled, while stress rats were given a variety of daily stressors administered twice per day for 6 consecutive days. One day after the last stress, rats were given a saline injection followed by a cocaine injection (15 mg/kg, i.p.) the next day, and locomotor activity was monitored (early withdrawal). Two weeks after the last stress, the locomotor responses to an additional saline and cocaine injection were monitored (late withdrawal). At early withdrawal, no significant sensitization occurred for horizontal activity, but cross-sensitization was demonstrated for vertical activity. At late withdrawal, sham controls showed a stress-induced elevation in horizontal activity, with only a trend toward increased vertical activity. Animals given ADX surgery or ADX and CORT 12.5% pellets did not demonstrate sensitization to repeated stress, while CORT 50% pellets in ADX rats restored the sensitized horizontal response to cocaine challenge at late withdrawal. In contrast, stress-pretreated rats which were given CORT 50% pellets during the 2-week withdrawal period after the stress showed a marked decrease in horizontal activity in response to cocaine challenge at late withdrawal. The results provide evidence for a necessary role for adrenal hormones in long term, but not short-term, stress-induced cross-sensitization. Together with our previous study on the role of CORT in cocaine-induced sensitization, the results indicate that CORT is not the common factor mediating the long-term sensitization to cocaine and stress.

Effect of adrenalectomy on the initiation and expression of cocaine-induced sensitization.

The role of corticosterone in the initiation and expression phases of sensitization to cocaine was examined. To determine the effect of corticosterone on the initiation of sensitization, male Sprague-Dawley rats were given a sham adrenalectomy (ADX), or ADX surgery. Approximately 1 week later, rats were given a cocaine (15 mg/kg, i.p.) injection on day 1. On days 2-6, rats were given cocaine (30 mg/kg, i.p.), and the next day, a cocaine challenge (15 mg/kg) was administered (= early withdrawal). Four days later, 50% of the ADX rats were given corticosterone pellets and corticosterone in the evening drinking water to mimic the circadian variation in corticosterone levels. After 1 week, rats were given a final saline challenge followed by a cocaine challenge (15 mg/kg) the next day (= late withdrawal). Locomotor activity was monitored after cocaine treatment on day 1 and after challenge at early and late withdrawal. Sham controls demonstrated a sensitized locomotor response to the cocaine challenge at early withdrawal, with a slight increase in this behavioral sensitization at the late withdrawal time. In contrast, sensitization was not observed in ADX rats after early withdrawal from cocaine, but this attenuation was not permanent, since ADX animals demonstrated control levels of sensitization by the late withdrawal time 12 days later. Animals given corticosterone replacement 1 week prior to the late cocaine challenge also demonstrated a sensitized response similar to control levels. The effect of corticosterone on the expression of sensitization was examined by administering daily cocaine as before followed by surgery a few days later. The treatment groups were sham, ADX and ADX+corticosterone replacement as described. Fourteen days later, a saline injection was given followed by a cocaine challenge the next day. Behavioral sensitization to a cocaine challenge was found in all three treatment groups. These data suggest that adrenal hormones are necessary during the initiation phase of sensitization when observed after early withdrawal (1 day), but not when sensitization is examined at a later withdrawal time (12 days). In addition, corticosterone levels do not significantly affect the expression phase of behavioral sensitization to cocaine.

Sensitization to stress and psychostimulants. Involvement of dopamine transmission versus the HPA axis.

Rats exposed to chronic stress demonstrate an enhanced motor response to psychostimulants, such as cocaine. This behavioral cross-sensitization between stress (repeated mild footshock) and cocaine (15 mg/kg, ip) is associated with an increase in extracellular dopamine in the nucleus accumbens, but a decrease in the prefrontal cortex. To determine a role for the hypothalamic-pituitary-adrenal axis in sensitization, rats were adrenalectomized prior to administering repeated cocaine injections. One and twelve days after discontinuing repeated cocaine, rats were challenged with acute cocaine. Adrenalectomy blocked the cocaine-induced sensitization observed in sham animals, but both the sham and adrenalectomized rats demonstrated behavioral sensitization to cocaine after twelve days of withdrawal. These data argue that while long-term alterations in dopamine transmission may be an important neurochemical substrate of stress and psychostimulant-induced sensitization, the hypothalamic-pituitary-adrenal axis may not have a necessary role.

Sustained depolarization decreases calcium/calmodulin-dependent protein kinase II activity and gene expression in dopamine neurons.

Altered gene expression mediated by calcium/calmodulin-dependent protein kinase II (CaMKII) and other intracellular signaling molecules plays an important role in activity-dependent neuroplasticity. We discovered that sustained depolarization induced by KCl, a commonly used paradigm for studying activity-dependent gene expression, surprisingly caused a decrease in CaMKII activity in rat mesencephalic dopamine neurons. This decrease in CaMKII activity, after 2 days of depolarization, occurred in the presence of a continued elevation in intracellular calcium concentration. An increase in calyculin-sensitive phosphatase activity was at least partly responsible for the decrease in CaMKII activity. Phosphatase assays revealed that activity but not the abundance of protein phosphatase-2A was increased by sustained depolarization. Decreased CaMKII activity was accompanied by a selective decrease in dopamine transporter (DAT) mRNA, while tyrosine hydroxylase and actin mRNA abundance was unaltered. On the other hand, brain-derived neurotrophic factor (BDNF) mRNA abundance was increased by sustained depolarization, further demonstrating the specificity of changes. Depolarization also caused a significant decrease in DAT protein abundance and DAT-mediated uptake. Taken together, these data illustrate a novel signaling paradigm in which the activity of protein phosphatase-2A is associated with CaMKII activity and gene expression.

Feed restriction in prepubertal lambs: effect on puberty onset and on in vivo release of luteinizing-hormone-releasing hormone, neuropeptide Y and beta-endorphin from the posterior-lateral median eminence.

The exact nature of the interaction between energy balance and reproduction is still elusive. Theoretically, nutrition-related variables must reach the hypothalamic luteinizing-hormone-releasing hormone (LHRH) network and/or its neuronal inputs, to alter plasma luteinizing hormone (LH) and therefore reproductive activity. In an attempt to assess the potential mechanism of such interaction at the median eminence (ME) level, the area of hypophysiotropic LHRH neuronal terminals and release, we used a decreased caloric intake lamb model which delays the onset of puberty. Thus, we determined the in vivo release of neuropeptides, by push-pull cannula (PPC) sampling from the posterior-lateral ME, in feed-restricted (FR) ewe lambs and in full-fed (FF), age-matched, contemporary control animals. Specifically, we assessed: (1) serum LH and ME in vivo release of LHRH, beta-endorphin (beta-END) and neuropeptide Y (NPY); beta-END and NPY are two putative neuronal inputs to LHRH neuronal terminals at the ME, reported to be involved in the control of both reproduction and feed intake; (2) the effect that exogenous infusion of beta-END through the PPC might have on the release of ME LHRH and NPY, and on plasma LH. In contrast to other works, the present results were obtained in lambs with intact ovaries. Furthermore, FR lambs were always compared statistically with FF contemporary paired controls that had attained puberty. Feed restriction decreased ME LHRH release, lowered plasma LH and prevented the onset of puberty. The changes induced by feed restriction in both LHRH and LH release were associated predominantly with decreases in pulse amplitude, rather than alterations in pulse frequency. The decreased LHRH and LH release occurred in the presence of a decreased beta-END but unchanged NPY release from the ME. Exogenous infusion of beta-END into the posterior-lateral ME decreased both LHRH and NPY release from this site and decreased plasma LH. In conclusion, decreased caloric intake lowers LH release and prevents puberty onset by decreasing the amplitude of the LHRH output from the hypothalamic hypophysiotropic network. A compensatory but unsuccessful mechanism for the FR status might be a lower beta-END-inhibitory tone on ME LHRH neuronal terminals. The unchanged release of NPY at this site supports the specificity of the changes induced by feed restriction on LHRH and beta-END in vivo release.

Repeated daily cocaine alters subsequent cocaine-induced increase of extracellular dopamine in the medial prefrontal cortex.

Male Sprague-Dawley rats that were naive or that had been treated with five daily saline or cocaine injections (15 mg/kg i.p.) were subsequently challenged with an injection of cocaine, and extracellular dopamine content in the medial prefrontal cortex (mPFC) was measured using in vivo microdialysis. Cocaine challenge increased extracellular dopamine levels from base line in all three groups of rats, but the augmentation was significantly reduced in the cocaine-pretreated group, compared with the saline-pretreated group. In contrast, mPFC dopamine levels were not different among groups after challenge with systemic d-amphetamine. To test whether repeated cocaine treatment led to altered releasability of dopamine from mPFC terminals, challenge with KCI (10, 30 or 100 mM) or d-amphetamine (3, 30 or 300 microM) was made via infusion through the dialysis probe into the mPFC. No differences in dopamine levels were found between treatment groups for either drug at any dose. To determine whether the effects of cocaine were mediated by local actions within mPFC dopamine terminals, a cocaine challenge was administered through the microdialysis probe (1, 10 or 100 microM). In contrast to the systemic cocaine challenge, local infusion of cocaine elicited a significant increase in daily cocaine-pretreated rats, compared with saline-pretreated controls, at the lowest dose tested, with no differences at the higher two doses. In summary, daily cocaine-pretreated rats demonstrated a suppressed mPFC dopamine response to subsequent systemic, but not local, cocaine challenge. The results suggest that this apparent tolerance is not due to altered releasability of dopamine from mPFC terminals and may rely on altered afferent regulation of mesocortical dopamine neurons.