Faraday-Cage-Type Electrochemiluminescence Immunoassay: A Rise of Advanced Biosensing Strategy.

Electrochemiluminescence immunoassays are usually carried out through "on-electrode" strategy, i.e., sandwich-type immunoassay format, the sensitivity of which is restricted by two key bottlenecks: (1) the number of signal labels is limited and (2) only a part of signal labels could participate in the electrode reaction. In this Perspective, we discuss the development of an "in-electrode" Faraday-cage-type concept-based immunocomplex immobilization strategy. The biggest difference from the traditional sandwich-type one is that the designed "in-electrode" Faraday-cage-type immunoassay uses a conductive two-dimensional (2-D) nanomaterial simultaneously coated with signal labels and a recognition component as the detection unit, which could directly overlap on the electrode surface. In such a case, electrons could flow freely from the electrode to the detection unit, the outer Helmholtz plane (OHP) of the electrode is extended, and thousands of signal labels coated on the 2-D nanomaterial are all electrochemically "effective." Thus, then, the above-mentioned bottlenecks obstructing the improvement of the sensitivity in sandwich-type immunoassay are eliminated, and as a result a much higher sensitivity of the Faraday-cage-type immunoassay can be obtained. And, the applications of the proposed versatile "in-electrode" Faraday-cage-type immunoassay have been explored in the detection of target polypeptide, protein, pathogen, and microRNA, with the detection sensitivity improved tens to hundreds of times. Finally, the outlook and challenges in the field are summarized. The rise of Faraday-cage-type electrochemiluminescence immunoassay (FCT-ECLIA)-based biosensing strategies opens new horizons for a wide range of early clinical identification and diagnostic applications.

SMART: Statistical Metabolomics Analysis-An R Tool.

Metabolomics data provide unprecedented opportunities to decipher metabolic mechanisms by analyzing hundreds to thousands of metabolites. Data quality concerns and complex batch effects in metabolomics must be appropriately addressed through statistical analysis. This study developed an integrated analysis tool for metabolomics studies to streamline the complete analysis flow from initial data preprocessing to downstream association analysis. We developed Statistical Metabolomics Analysis-An R Tool (SMART), which can analyze input files with different formats, visually represent various types of data features, implement peak alignment and annotation, conduct quality control for samples and peaks, explore batch effects, and perform association analysis. A pharmacometabolomics study of antihypertensive medication was conducted and data were analyzed using SMART. Neuromedin N was identified as a metabolite significantly associated with angiotensin-converting-enzyme inhibitors in our metabolome-wide association analysis (p = 1.56 × 10(-4) in an analysis of covariance (ANCOVA) with an adjustment for unknown latent groups and p = 1.02 × 10(-4) in an ANCOVA with an adjustment for hidden substructures). This endogenous neuropeptide is highly related to neurotensin and neuromedin U, which are involved in blood pressure regulation and smooth muscle contraction. The SMART software, a user guide, and example data can be downloaded from http://www.stat.sinica.edu.tw/hsinchou/metabolomics/SMART.htm .

Elevated Neuropeptides in Dry Eye Disease and Their Clinical Correlations.

PURPOSE: The goal of this study was to assess neuropeptide levels in patients with dry eye disease (DED) and investigate their correlations with clinical characteristics. METHODS: This study included 38 eyes of 38 patients diagnosed with DED (DED group) and 38 eyes of 38 healthy volunteers without DED (control group). Ocular surface evaluation was performed. The severity of dry eye symptoms and signs in the DED group was graded. Neuropeptides [substance P (SP), alpha-melanocyte-stimulating hormone (α-MSH), ß-endorphin, neurotensin, and oxytocin] and inflammatory cytokines levels were measured in basal tears. The link between neuropeptides and clinical parameters was investigated using Spearman rank correlation. RESULTS: Overall, 76.3% of patients in the DED group showed dry eye symptoms and signs that were inconsistent in severity. Compared with the control group, the DED group showed higher levels of SP, α-MSH, and oxytocin in tears (P = 0.012, P = 0.030, and P = 0.006, respectively), but similar levels of ß-endorphin and neurotensin (P = 0.269 and P = 0.052). The levels of SP, α-MSH, and oxytocin were elevated in DED patients with higher grading of symptoms than clinical signs (all P < 0.05). SP, α-MSH, and oxytocin levels in tears were positively correlated with Ocular Surface Disease Index scores, frequency of sensitivity to light, and frequency of blurred vision (all P < 0.05). CONCLUSIONS: The increased tear levels of SP, α-MSH, and oxytocin may be linked to ocular discomfort in DED. Neuropeptides may play a key role in the development of DED, especially in DED patients with more severe symptoms than clinical signs.

Solid-phase extraction-field-amplified sample injection coupled with CE-ESI-MS for online pre-concentration and quantitative analysis of brain-gut peptides.

In order to improve the sensitivity of CE-ESI-MS for the analysis of brain-gut peptides, a solid-phase extraction combined with field-amplified sample injection was used for the pre-concentration of the brain-gut peptides. Compared with the conventional pressure injection method, the sensitivity in the detection of brain-gut peptides was improved more than 100-fold. The possible factors affecting sample stacking, such as the sample matrix, the composition and the length of the water column, the types and the volumes of eluent, have been investigated in detail. Under the optimum conditions, the detectable concentration of brain-gut peptides was found to be as low as 0.02 µM. A linear response concentration for the detection was developed in the range of 0.08-25 µmol/L. A real sample of human cerebrospinal fluids, which was spiked with brain-gut peptides, was also examined in order to evaluate the reliability of the proposed approach. The recovery of the method was in a range from 69.2 to 85.4%. The method was found to be reliable, accurate and potentially applicable for clinical drug analysis.

Comparative analysis of the ERα/ERß ratio and neurotensin and its high-affinity receptor in myometrium, uterine leiomyoma, atypical leiomyoma, and leiomyosarcoma.

Deregulated steroids are involved in different hormone-dependent tumors, including benign and malignant uterine neoplasms. Leiomyomas (LM) are estrogen and progesterone-dependent benign tumors, whereas "bizarre or atypical LMs" (AL) are considered a subgroup of LM and clinically benign, although their malignant potential is suspect. Uterine leiomyosarcomas (LMS) are malignant smooth muscle tumors, and ovarian steroids may control their growth. Estrogen effects are mediated by 2 receptors, estrogen receptors (ER) α and ß, and the ratio of both receptors seems to be a critical parameter in the estrogen-mediated carcinogenic process. Estradiol induces the expression of neurotensin (NTS), and the coupling of this peptide with its high-affinity receptor, NTS1, has been involved in the regulation of tumoral cell growth. Given the importance of these markers in tumor development, we aim to determine the status of ERα and ERß in the myometrium and LM, AL, and LMS, concomitantly with the expression of NTS/NTS receptor 1 in these tumors. For that purpose, we use immunohistochemistry for all markers analyzed and in-situ hybridization to detect NTS mRNA. These data suggest that LMS are estrogen-dependent tumors, which may use NTS as an autocrine growth factor. In addition, the phenotype of AL with regard to ERα and ERß status and NTS expression is closer to LMS than LM; thus, a potential malignization of this tumor is feasible.

Metabolically stable neurotensin analogs exert potent and long-acting analgesia without hypothermia.

The endogenous tridecapeptide neurotensin (NT) has emerged as an important inhibitory modulator of pain transmission, exerting its analgesic action through the activation of the G protein-coupled receptors, NTS1 and NTS2. Whereas both NT receptors mediate the analgesic effects of NT, NTS1 activation also produces hypotension and hypothermia, which may represent obstacles for the development of new pain medications. In the present study, we implemented various chemical strategies to improve the metabolic stability of the biologically active fragment NT(8-13) and assessed their NTS1/NTS2 relative binding affinities. We then determined their ability to reduce the nociceptive behaviors in acute, tonic, and chronic pain models and to modulate blood pressure and body temperature. To this end, we synthesized a series of NT(8-13) analogs carrying a reduced amide bond at Lys8-Lys9 and harboring site-selective modifications with unnatural amino acids, such as silaproline (Sip) and trimethylsilylalanine (TMSAla). Incorporation of Sip and TMSAla respectively in positions 10 and 13 of NT(8-13) combined with the Lys8-Lys9 reduced amine bond (JMV5296) greatly prolonged the plasma half-life time over 20 h. These modifications also led to a 25-fold peptide selectivity toward NTS2. More importantly, central delivery of JMV5296 was able to induce a strong antinociceptive effect in acute (tail-flick), tonic (formalin), and chronic inflammatory (CFA) pain models without inducing hypothermia. Altogether, these results demonstrate that the chemically-modified NT(8-13) analog JMV5296 exhibits a better therapeutic profile and may thus represent a promising avenue to guide the development of new stable NT agonists and improve pain management.

Dorsomedial SCN neuronal subpopulations subserve different functions in human dementia.

The suprachiasmatic nuclei (SCN) are necessary and sufficient for the maintenance of circadian rhythms in primate and other mammalian species. The human dorsomedial SCN contains populations of non-species-specific vasopressin and species-specific neurotensin neurons. We made time-series recordings of core body temperature and locomotor activity in 19 elderly, male, end-stage dementia patients and 8 normal elderly controls. Following the death of the dementia patients, neuropathological diagnostic information and tissue samples from the hypothalamus were obtained. Hypothalamic tissue was also obtained from eight normal control cases that had not had activity or core temperature recordings previously. Core temperature was analysed for parametric, circadian features, and activity was analysed for non-parametric and parametric circadian features. These indices were then correlated with the degree of degeneration seen in the SCN (glia/neuron ratio) and neuronal counts from the dorsomedial SCN (vasopressin, neurotensin). Specific loss of SCN neurotensin neurons was associated with loss of activity and temperature amplitude without increase in activity fragmentation. Loss of SCN vasopressin neurons was associated with increased activity fragmentation but not loss of amplitude. Evidence for a circadian rhythm of vasopressinergic activity was seen in the dementia cases but no evidence was seen for a circadian rhythm in neurotensinergic activity. These results provide evidence that the SCN is necessary for the maintenance of the circadian rhythm in humans, information on the role of neuronal subpopulations in subserving this function and the utility of dementia in elaborating brain-behaviour relationships in the human.

Mapping the populations of neurotensin neurons in the male mouse brain.

Neurotensin (Nts) is a neuropeptide implicated in the regulation of many facets of physiology, including cardiovascular tone, pain processing, ingestive behaviors, locomotor drive, sleep, addiction and social behaviors. Yet, there is incomplete understanding about how the various populations of Nts neurons distributed throughout the brain mediate such physiology. This knowledge gap largely stemmed from the inability to simultaneously identify Nts cell bodies and manipulate them in vivo. One means of overcoming this obstacle is to study NtsCre mice crossed onto a Cre-inducible green fluorescent reporter line (NtsCre;GFP mice), as these mice permit both visualization and in vivo modulation of specific populations of Nts neurons (using Cre-inducible viral and genetic tools) to reveal their function. Here we provide a comprehensive characterization of the distribution and relative densities of the Nts-GFP populations observed throughout the male NtsCre;GFP mouse brain, which will pave the way for future work to define their physiologic roles. We also compared the distribution of Nts-GFP neurons with Nts-In situ Hybridization (Nts-ISH) data from the adult mouse brain. By comparing these data sets we can distinguish Nts-GFP populations that may only transiently express Nts during development but not in the mature brain, and hence which populations may not be amenable to Cre-mediated manipulation in adult NtsCre;GFP mice. This atlas of Nts-GFP neurons will facilitate future studies using the NtsCre;GFP line to describe the physiological functions of individual Nts populations and how modulating them may be useful to treat disease.

Immunohistochemical distribution of regulatory peptides in the human fetal adenohypophysis.

We have studied here the cellular distribution of several regulatory peptides in hormone-producing cells of the human pituitary during the fetal period. Immunohistochemistry was used to show the expression of several regulatory peptides, namely Angiotensin-II, Neurotensin and Galanin, at successive gestational stages and their co-localization with hormones in the human fetal adenohypophysis. Somatotrophs, gonadotrophs and thyrotrophs were differentiated earliest. At gestational week 9, Angiotensin-II immunoreactivity was co-localized only with growth hormone immunoreactivity in somatotrophs, one of the first hormone-producing cells to differentiate. This co-localization remained until week 37. Neurotensin immunoreactivity was present in gonadotrophs and thyrotrophs in week 23, after FSH and TSH hormone differentiation. Galanin immunoreactivity was present in all hormone-producing cell types except corticotrophs. The different pro-opiomelanocortin-derived peptides were detected at different stages of gestation and adrenocorticotrophic hormone immunoreaction was the last to be detected. Our results show an interesting relationship between regulatory peptides and hormones during human fetal development, which could imply that these peptides play a regulatory role in the development of pituitary function.

Separation and determination of peptide hormones by capillary electrophoresis with laser-induced fluorescence coupled with transient pseudo-isotachophoresis preconcentration.

A new method for the determination of the peptide hormones and their fragments by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection and transient pseudo-isotachophoresis (pseudo-tITP) preconcentration was established in this study. The LIF detector used an argon ion laser with excitation wavelength at 488 nm and emission wavelength at 535 nm. Fluorescein isothiocyanate (FITC) was used as precolumn derivatization reagent to label cholecystokinin tetrapeptide (CCK-4), neurotensin (NT), neurotensin hexapeptide (NT(8-13)), and neurokinin B (NKB). Borate (10 mmol/L, pH 9.0) was selected as derivatization medium to get the high efficiency. When the addition of 70% (v/v) methanol and 1% (m/v) sodium chloride (NaCl) to the sample matrix, and with borate buffer (110 mM, pH 9.5) and 20% (v/v) methanol as running buffer, a preconcentration based on the pseudo-tITP afforded 100-fold improvement in peak heights compared with the traditional hydrodynamic injection (2.3% capillary volume). The detection limits (signal/noise=3) based on peak height were found to be 0.04, 0.1, 0.2, and 0.08 nmol/L for NT(8-13), NT, NKB, and CCK-4, respectively. The method was validated and applied to qualitative analysis of NT and NT(8-13) in human cerebrospinal fluid sample.

A constant-momentum/energy-selector time-of-flight mass spectrometer.

A matrix assisted laser desorption/ionization time-of-flight mass spectrometer has been built with an ion source that can be operated in either constant-energy or constant-momentum acceleration modes. A decreasing electric field distribution in the ion-accelerating region makes it possible to direct ions onto a space-focal plane in either modes of operation. Ions produced in the constant-momentum mode have velocities and, thus, flight times that are linearly dependent on mass and kinetic energies that are inversely dependent on mass. The linear mass dispersion doubles mass resolving power of ions accelerated with space-focusing conditions in constant-momentum mode. The mass-dependent kinetic energy is exploited to disperse ions according to mass in a simple kinetic energy filter constructed from two closely spaced, oblique ion reflectors. Focusing velocity of ions of the same mass can substantially improve ion selection for subsequent post source decay or tandem time-of-flight analyses.

Early dexamethasone treatment after implantation of a sciatic-nerve cuff decreases the concentration of substance P in the lumbar spinal cord of rats with neuropathic pain.

The main purpose of this study was to evaluate the effects of early dexamethasone treatment on pain-related peptides at an early stage in the development of neuropathic pain induced by implantation of a sciatic nerve cuff in Sprague Dawley rats (body weight 250 to 350 g). The rats were tested for touch sensitivity with the use of von Frey filaments before and 3 d after cuff implantation (n = 12) or sham surgery (n = 6). Half of the cuff-implanted rats received dexamethasone, 1 mg/kg intraperitoneally, 1 h after surgery. Spinal cords were collected on the 3rd day after surgery, and the lumbar enlargement was processed for the detection of selected peptides (neurotensin, substance P, cholecystokinin [CCK], vasoactive intestinal peptide, and calcitonin gene-related peptide) by means of liquid chromatography and tandem mass spectrometry. The right sciatic nerve of each rat was collected, fixed, and stained for histopathological evaluation. Except for neurotensin, all the peptides showed an increased concentration with neuropathic pain; however, the differences were significant (P < 0.05) only for substance P and CCK. In the animals treated with dexamethasone, mechanical allodynia was less pronounced (P < 0.01), and only the concentration of substance P was decreased significantly (P < 0.05). Sciatic nerve sections showed a decrease in C (P < 0.01) and Adelta (P < 0.03) fibres with neuropathic pain and a nearly normal percentage of C fibres after dexamethasone treatment. The dexamethasone-treated animals also had less inflammation detectable microscopically at the nerve constriction site compared with cuff-implanted animals that were not treated with dexamethasone. Our results suggest that in the early stages of neuropathic pain induced by an inflammatory process, dexamethasone may be a useful treatment and that substance P plays an important role in pain perception.

Acquisition of neuroendocrine characteristics by prostate tumor cells is reversible: implications for prostate cancer progression.

Neuroendocrine (NE) cells occur as scattered foci within prostatic adenocarcinoma, similar to their distribution within ductal epithelial cells of the normal prostate. However, the density of NE cells is often greater in prostate carcinomas than in normal tissue, and the frequency of NE cells correlates with tumor grade, loss of androgen sensitivity, autocrine/paracrine activity, and poor prognosis. Although NE cells are nonmitotic, proliferating cells are found in direct proximity to them, suggesting that NE cells provide paracrine stimuli for surrounding carcinoma cells. In vitro, differentiation of the LNCaP and PC3M prostatic tumor cell lines to a NE phenotype can be induced by dibutyryl cyclic AMP (cAMP), suggesting that physiological agents that increase intracellular concentrations of cAMP might regulate NE differentiation in vivo. Indeed, we demonstrate in this report that LNCaP cells acquire NE characteristics in response to treatment with physiological and pharmacological agents that elevate intracellular cAMP, agents such as epinephrine, isoproterenol, forskolin, and dibutyryl cAMP. The androgen-independent LNCaP-derived cell line C4-2 also responded to these agents, indicating that cells representing later stages of tumor progression are also capable of differentiation. The NE phenotype in this study was monitored by the appearance of dense core granules in the cytoplasm, the extension of neuron-like processes, loss of mitogenic activity, and expression of the NE markers neuron-specific enolase, parathyroid hormone-related peptide, neurotensin, serotonin, and chromogranin A. However, contrary to previous reports, we observed rapid loss of the NE phenotype in both LNCaP and C4-2 cells upon withdrawal of inducing agents. Withdrawal also resulted in a rapid, dramatic increase in tyrosine kinase and mitogen-activated protein kinase activities, suggesting that activation of these intracellular signaling enzymes may be important for reentry into the cell cycle. Together, these results indicate that chronic cAMP-mediated signaling is required to block proliferation of prostate tumor cells and to induce NE differentiation.

In-electrode vs. on-electrode: ultrasensitive Faraday cage-type electrochemiluminescence immunoassay.

A new-concept of an "in-electrode" Faraday cage-type electrochemiluminescence immunoassay (ECLIA) method for the ultrasensitive detection of neurotensin (NT) was reported with capture antibody (Ab1)-nanoFe3O4@graphene (GO) and detector antibody (Ab2)&N-(4-aminobutyl)-N-ethylisoluminol (ABEI)@GO, which led to about 1000-fold improvement in sensitivity by extending the Helmholtz plane (OHP) of the proposed electrode assembly effectively.

NTS/NTR1 co-expression enhances epithelial-to-mesenchymal transition and promotes tumor metastasis by activating the Wnt/ß-catenin signaling pathway in hepatocellular carcinoma.

Neurotensin (NTS) is a neuropeptide distributed in central nervous and digestive systems. In this study, the significant association between ectopic NTS expression and tumor invasion was confirmed in hepatocellular carcinoma (HCC). In primary HCC tissues, the NTS and neurotensin receptor 1 (NTR1) co-expression (NTS+NTR1+) is a poor prognostic factor correlated with aggressive biological behaviors and poor clinical prognosis. Enhanced epithelial-to-mesenchymal transition (EMT) features, including decreased E-cadherin, increased ß-catenin translocation and N-cadherin expression, were identified in NTS+NTR1+ HCC tissues. Varied NTS-responsible HCC cell lines were established using NTR1 genetically modified Hep3B and HepG2 cells which were used to elucidate the molecular mechanisms regulating NTS-induced EMT and tumor invasion in vitro. Results revealed that inducing exogenous NTS stimulation and enhancing NTR1 expression promoted tumor invasion rather than proliferation by accelerating EMT in HCC cells. The NTS-induced EMT was correlated with the remarkable increase in Wnt1, Wnt3, Wnt5, Axin, and p-GSK3ß expression and was significantly reversed by blocking the NTS signaling via the NTR1 antagonist SR48692 or by inhibiting the activation of the Wnt/ß-catenin pathway via specific inhibitors, such as TSW119 and DKK-1. SR48692 also inhibited the metastases of NTR1-overexpressing HCC xenografts in the lungs in vivo. This finding implied that NTS may be an important stimulus to promote HCC invasion and metastasis both in vitro and in vivo, and NTS signaling enhanced the tumor EMT and invasion potentials by activating the canonical Wnt/ß-catenin signaling pathway. Therefore, NTS may be a valuable therapeutic target to prevent tumor progression in HCC.

Ciproxifan, a histamine H3-receptor antagonist/inverse agonist, potentiates neurochemical and behavioral effects of haloperidol in the rat.

By using double in situ hybridization performed with proenkephalin and H3-receptor riboprobes on the same sections from rat brain, we show that histamine H3 receptors are expressed within striatopallidal neurons of the indirect movement pathway. The majority ( approximately 70%) of striatal enkephalin neurons express H3-receptor mRNAs. This important degree of coexpression of proenkephalin and H3-receptor mRNAs prompted us to explore the effect of H3-receptor ligands on the regulation of enkephalin mRNA expression in the striatum. Acute administration of ciproxifan, a H3-receptor antagonist/inverse agonist, did not modify the expression of the neuropeptide by itself but strongly increased the upregulation of its expression induced by haloperidol. This potentiation (1) was suppressed by the administration of (R)-alpha-methylhistamine, a H3-receptor agonist, (2) occurred both in the caudate-putamen and nucleus accumbens, and (3) was also observed with a similar pattern on c-fos and neurotensin mRNA expression. Similarly, whereas it was devoid of any motor effect when used alone, ciproxifan strongly potentiated haloperidol-induced locomotor hypoactivity and catalepsy, two behaviors in which striatal neurons are involved. The strong H3-receptor mRNA expression in enkephalin neurons suggests that the synergistic neurochemical and motor effects of ciproxifan and haloperidol result from direct H3/D2-receptor interactions, leading to an enhanced activation of striatopallidal neurons of the indirect movement pathway. The potentiation of the effects of haloperidol by ciproxifan strengthens the potential interest of H3-receptor antagonists/inverse agonists to improve the symptomatic treatment of schizophrenia.

Localization of neurotensin immunoreactivity in neurons and organ of Corti of rat cochlea.

The distribution of neurotensin-containing cell bodies and fibers has been observed in the central and peripheral nervous system, including sensory ganglia, but no description has been found in the peripheral auditory system. Here, we investigated the presence of neurotensin immunoreactivity in the cochlea of the adult Wistar rat. Strong neurotensin immunoreactivity was detected in the cytoplasm of the inner hair cells (IHC) and Deiters' cells of the organ of Corti. Outer hair cells (OHC) show weak immunoreaction. Neurotensin immunoreactivity was also found in the neurons and fibers of the spiral ganglia. Quantitative microdensitometric image analysis of the neurotensin immunoreactivity showed a strong immunoreaction in the hair cells of organ of Corti and a moderate to strong labeling in the spiral ganglion neurons. A series of double immunolabeling experiments demonstrated a strong neurotensin immunoreactivity in the parvalbumin immunoreactive IHC and also in the calbindin immunoreactive Deiters' cells. Weak neurotensin immunoreactivity was seen in the calbindin positive OHC. Neurofilament and parvalbumin immunoreactive neurons and fibers in the spiral ganglia showed neurotensin immunoreactivity. Calbindin immunoreactivity was not detected in the spiral ganglion neurons, which are labeled by neurotensin immunoreactivity. The presence of neurotensin in the cochlea may be related to its modulation of neurotransmission in the peripheral auditory pathway.

Noradrenaline, atrial natriuretic peptide, bombesin and neurotensin in myocardium and blood of rats in congestive cardiac failure.

Rats given monocrotaline develop severe right ventricular hypertrophy often accompanied by ascites and pleural effusions. In rats with right ventricular hypertrophy and no serous effusions ("hypertrophy" group), ventricular concentrations of noradrenaline were reduced but ventricular contents were unchanged. Atrial concentrations of noradrenaline were unaffected. Those with more severe right ventricular hypertrophy and serous effusions ("failure" group) had greatly reduced concentrations of noradrenaline in all four chambers, particularly on the right side; the right and left ventricular contents of noradrenaline were also diminished. The distributions of ir-ANP, ir-bombesin and ir-neurotensin in the normal rat heart are presented. ANP concentration fell to 33% in the right atrium and 46% in the left atrium of "failure" animals and to 57% in the right atrium of "hypertrophy" animals. Right ventricular content of ANP, normally low, increased more than two-fold in both groups, the concentration remaining unchanged. Left ventricular content of ANP decreased in the "failure" group. Concentrations of bombesin and neurotensin fell in both ventricles of both groups. Ventricular contents of bombesin did not change, but ventricular contents of neurotensin decreased, especially on the right side. Plasma ANP rose nearly six-fold while plasma bombesin and neurotensin fell in the "failure" group. Plasma peptide concentrations were unchanged in the "hypertrophy" group. The studies show the utility of the monocrotaline model in distinguishing between the effects of hypertrophy and those associated specifically with the syndrome of congestive cardiac failure.

Neurotensin-like immunoreactivity in a subpopulation of noradrenaline-containing cells of the cat adrenal gland.

RIA of cat adrenal tissue extracts revealed a neurotensin-like immunoreactive material concentrated within the medulla of the gland (mean +/- SEM neurotensin concentration, 15.2 +/- 3.6 pmol/g whole gland; 47.9 +/- 18.4 pmol/g microdissected medulla). This immunoreactive material was found to elute in the region of synthetic neurotensin, thus indicating a similarity to the tridecapeptide originally isolated from bovine hypothalamus. Using immunocytochemical procedures at both light and ultrastructural levels, a neurotensin-like immunoreactive material was localized to a subpopulation of noradrenaline-containing cells quite distinct from the previously described enkephalin-immunoreactive chromaffin cells. Correlative ultrastructural observations have identified three morphologically distinct types of chromaffin cells in the medulla, indicating a marked heterogeneity within the noradrenaline cell population. The finding of neurotensin-like immunoreactivity in noradrenaline-containing cells of the cat adrenal medulla provides further evidence in support of the postulated existence of heterogeneous subpopulations of noradrenaline-containing cells and suggests a possible functional interrelationship between neurotensin and catecholamine.

Neurotensin neurons in the rat hypothalamus: an immunocytochemical study.

Neurotensin was localized in the hypothalamic tissues of adult Sprague-Dawley rats by immunoperoxidase techniques. Visualization of perikarya was greatly enhanced by intraventricular administration of colchicine. Many perikarya containing neurotensin-like immunoreactivity were seen in the medial preoptic area, the periventricular hypothalamus, the parvocellular portion of the paraventricular nucleus, the arcuate nucleus, and the lateral hypothalamus in the perifornical area. There were moderate numbers of cell bodies in the ventral portion of the anterior hypothalamus, the dorsomedial nucleus, and the posterior hypothalamus. No positive cells were seen in the suprachiasmatic, ventromedial, or mammillary nuclei. Reactive fibers were generally distributed in the same regions as cell bodies. Additional dense collections were seen in the lateral part of the zona externa of the median eminence, the pituitary stalk, the posterior mammillary nucleus, and the most lateral portions of the hypothalamus at the medial edge of the crura cerbri. There were smaller numbers of fibers found in the pre-mammillary and posterior hypothalamic nuclei and the posterior pituitary gland. These results indicate that the neurotensin system in the hypothalamus is very extensive and complex, as it is in many other brain regions. Neurons and fibers are found in many hypothalamic areas, including projections to the hypophysial portal system in the median eminence, suggesting that neurotensin may affect neuroendocrine mechanisms at several levels, including the anterior pituitary gland.