Mephedrone alters basal ganglia and limbic neurotensin systems.

Mephedrone (4-methylmethcathinone) is a synthetic cathinone designer drug that alters pre-synaptic dopamine (DA) activity like many psychostimulants. However, little is known about the post-synaptic dopaminergic impacts of mephedrone. The neuropeptide neurotensin (NT) provides inhibitory feedback for basal ganglia and limbic DA pathways, and post-synaptic D1 -like and D2 -like receptor activity affects NT tissue levels. This study evaluated how mephedrone alters basal ganglia and limbic system NT content and the role of NT receptor activation in drug consumption behavior. Four 25 mg/kg injections of mephedrone increased NT content in basal ganglia (striatum, substantia nigra and globus pallidus) and the limbic regions (nucleus accumbens core), while a lower dosage (5 mg/kg/injection) only increased striatal NT content. Mephedrone-induced increases in basal ganglia NT levels were mediated by D1 -like receptors in the striatum and the substantia nigra by both D1 -like and D2 -like receptors in the globus pallidus. Mephedrone increased substance P content, another neuropeptide, in the globus pallidus, but not in the dorsal striatum or substantia nigra. Finally, the NT receptor agonist PD149163 blocked mephedrone self-administration, suggesting reduced NT release, as indicated by increased tissue levels, likely contributing to patterns of mephedrone consumption.

Endogenous neurotensin is involved in estrous cycle related alterations in prepulse inhibition of the acoustic startle reflex in female rats.

Ovarian hormones regulate prepulse inhibition (PPI) of the acoustic startle reflex. Results from studies in intact female rodents investigating sex, estrous cycle and ovarian hormone regulation of PPI are inconsistent. In experiment #1, we investigated whether PPI in female rats is influenced by the time of day of testing and the estrous cycle stage of the rat. PPI was examined across the day of proestrus (P) and diestrus 1 (D1) in female rats and compared to males. PPI in males and P females was significantly higher than in D1 females. PPI in males and D1 females was significantly affected by the time of day of testing with PPI being reduced in the afternoon and evening compared to morning. PPI in P females was not significantly affected by the time of day of testing. Previous studies have demonstrated estrous cycle regulation of central nervous system neurotensin (NT) neurons and peripherally administered NT receptor agonists regulate PPI in a manner similar to antipsychotic drugs. Experiment #2 of this study was designed to examine whether endogenous NT is involved in estrous cycle regulation of PPI. The NT receptor antagonist SR 142948A reduced the high levels of PPI during D1 and P. In contrast, when tested at a time of day in which PPI was low in D1 females, administration of both the typical antipsychotic drug haloperidol and the NT receptor antagonist significantly increased PPI. These data support an effect of time of day and estrous cycle stage on PPI in female rats. The estrous cycle variations in PPI are mediated in part by endogenous NT.

Investigation of ligand-receptor systems by high-resolution solid-state NMR: recent progress and perspectives.

Solid-state Nuclear Magnetic Resonance (NMR) provides a general method to study molecular structure and dynamics in a non-crystalline and insoluble environment. We discuss the latest methodological progress to construct 3D molecular structures from solid-state NMR data obtained under magic-angle-spinning conditions. As shown for the neurotensin/NTS-1 system, these methods can be readily applied to the investigation of ligand-binding to G-protein coupled receptors.

Altered neurotensin mrna expression in mice lacking the dopamine transporter.

Psychostimulants and antipsychotic drugs increase mRNA expression of the neuropeptide neurotensin (NT) in the striatum and nucleus accumbens. In the present study, we used mice lacking the dopamine transporter (DAT) to investigate the consequences of a chronic hyperdopaminergic state on NT gene expression. NT mRNA expression was examined under basal conditions and after administration of haloperidol or amphetamine using in situ hybridization with a digoxigenin-labeled NT cRNA probe. DAT-/- mice exhibited a striking increase in the number of NT mRNA-expressing perikarya in the substantia nigra and ventral tegmental area, as well as a less pronounced increase in the lateral septum compared with wild-type littermates. No changes were detected in other regions expressing NT mRNA. Acute administration of haloperidol (1 mg/kg) induced a significant increase in the number of NT mRNA-expressing neurons in the dorsomedial and dorsolateral striatum of wild-type mice but failed to stimulate NT gene expression in DAT mutants. In contrast, a higher dose of haloperidol (5 mg/kg) stimulated striatal NT mRNA expression both in DAT+/+ and DAT-/- mice. Amphetamine (10 mg/kg) increased the number of hybridized neurons in the nucleus accumbens shell and fundus striati of wild-type and DAT-/- mice, indicating that the drug acted through a target other than DAT, such as the serotonin or the norepinephrine transporters. The up-regulation of NT mRNA observed in DAT-/- mice may represent an adaptive mechanism in response to constitutive hyperdopaminergia. These results illustrate the profound alterations in the NT system induced by chronic stimulation of DA receptors and underscore the potential clinical relevance of NT/DA interactions in schizophrenia and drug abuse.

Prostaglandins mediate lipopolysaccharide effects upon cholecystokinin and neurotensin phenotypes in neuroendocrine corticotropin-releasing hormone neurons: in situ hybridization evidence in the rat.

Intraperitoneal injection of the endotoxin lipopolysaccharide produces an inflammation accompanied by immune system activation and secretion of cytokines that stimulate the hypothalamo-pituitary-adrenal (HPA) axis to release the anti-inflammatory corticosterone. Upstream in HPA axis are neuroendocrine corticotropin-releasing hormone neurons in the paraventricular nucleus whose multipeptidergic phenotype changes during inflammation: coexisting corticotropin-releasing hormone and cholecystokinin mRNAs are up-regulated whereas neurotensin mRNA expression is induced de novo. These changes may be mediated by prostaglandins released from perivascular and microglial cells in response to circulating cytokines. We examined by quantitative in situ hybridization histochemistry whether blockade of prostaglandin synthesis by indomethacin alters phenotypic expression in paraventricular nucleus neurons after lipopolysaccharide. Because indomethacin also elevated circulating corticosterone, animals were adrenalectomized and corticosterone replaced. Results showed that i.p. indomethacin administration suppressed lipopolysaccharide effects in a phenotype non-specific manner: one injection was sufficient to prevent both the increase in corticotropin-releasing hormone and cholecystokinin mRNAs expression and the induction of neurotensin mRNA expression. Therefore, neuroendocrine corticotropin-releasing hormone neurons with different peptidergic phenotypes appear to respond as a whole in the acute phase response to systemic infection.

Ciproxifan, a histamine H3-receptor antagonist/inverse agonist, modulates the effects of methamphetamine on neuropeptide mRNA expression in rat striatum.

We have explored the effect of histamine H3-receptor ligands on the regulation of neuropeptide mRNA expression in the striatum by using in situ hybridization performed with proenkephalin, prodynorphin, substance P and proneurotensin riboprobes. Acute administration of ciproxifan, an H3-receptor antagonist/inverse agonist, or (R)-alpha-methylhistamine, an H3-receptor agonist, did not modify the striatal expression of the neuropeptides by itself. However, ciproxifan strongly and differentially modulated the effect of a single administration of 3 mg/kg methamphetamine on neuropeptide mRNA expression. This modulation was suppressed by the administration of (R)-alpha-methylhistamine and occurred in both the caudate-putamen and nucleus accumbens. Ciproxifan strongly potentiated the decrease of proenkephalin mRNA expression induced by methamphetamine. In contrast, it suppressed the increase in prodynorphin and substance P mRNA expression induced by methamphetamine. Methamphetamine alone or with ciproxifan did not modify proneurotensin mRNA expression. These neurochemical findings indicate that ciproxifan differentially regulates the effect of methamphetamine on the neuropeptides contained in striatonigral and striatopallidal neurons. They suggest that endogenous histamine and dopamine cooperate to modulate the activity of striatal projection neurons and strengthen the interest of H3-receptors as new targets for the treatment of psychotic disorders and drug abuse.

The role of neurotensin in the pathophysiology of schizophrenia and the mechanism of action of antipsychotic drugs.

It has become increasingly clear that schizophrenia does not result from the dysfunction of a single neurotransmitter system, but rather pathologic alterations of several interacting systems. Targeting of neuropeptide neuromodulator systems, capable of concomitantly regulating several transmitter systems, represents a promising approach for the development of increasingly effective and side effect-free antipsychotic drugs. Neurotensin (NT) is a neuropeptide implicated in the pathophysiology of schizophrenia that specifically modulates neurotransmitter systems previously demonstrated to be dysregulated in this disorder. Clinical studies in which cerebrospinal fluid (CSF) NT concentrations have been measured revealed a subset of schizophrenic patients with decreased CSF NT concentrations that are restored by effective antipsychotic drug treatment. Considerable evidence also exists concordant with the involvement of NT systems in the mechanism of action of antipsychotic drugs. The behavioral and biochemical effects of centrally administered NT remarkably resemble those of systemically administered antipsychotic drugs, and antipsychotic drugs increase NT neurotransmission. This concatenation of findings led to the hypothesis that NT functions as an endogenous antipsychotic. Moreover, typical and atypical antipsychotic drugs differentially alter NT neurotransmission in nigrostriatal and mesolimbic dopamine (DA) terminal regions, and these effects are predictive of side effect liability and efficacy, respectively. This review summarizes the evidence in support of a role for the NT system in both the pathophysiology of schizophrenia and the mechanism of action of antipsychotic drugs.

The effects of glutamate receptor agonists on neurotensin release using in vivo microdialysis.

In the present study, extracellular concentrations of neurotensin were measured from the striatum, nucleus accumbens and the medial prefrontal cortex in the awake, freely moving rat. Using a highly sensitive solid phase radioimmunoassay, basal concentrations of neurotensin were 2-5 pg/sample. In each region, glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and kainic acid, increased neurotensin release 2-3-fold. Preincubation with the Na(+) channel blocker tetrodotoxin abolished the glutamate receptor agonist-induced increases except in the striatum following kainic acid infusion. These findings indicate that activation of glutamate receptors may indirectly stimulate neurotensin release.

Neurotensin gene expression and behavioral responses following administration of psychostimulants and antipsychotic drugs in dopamine D(3) receptor deficient mice.

Exposure to psychostimulants and antipsychotics increases neurotensin (NT) gene expression in the striatum and nucleus accumbens. To investigate the contribution of D(3) receptors to these effects we used mice with targeted disruption of the D(3) receptor gene. Basal NT mRNA expression was similar in D(3) receptor mutant mice and wild-type animals. Acute administration of haloperidol increased NT gene expression in the striatum in D(3)+/+, D(3)+/- and D(3)-/- mice. Similarly, acute cocaine and amphetamine induced NT mRNA expression in the nucleus accumbens shell and olfactory tubercle to a comparable extent in D(3) mutants and wild-type mice. Daily injection of cocaine for seven days increased NT mRNA in a restricted population of neurons in the dorsomedial caudal striatum of D(3)+/+ mice, but not in D(3)-/- and D(3)+/- animals. No differences were observed between D(3) receptor mutant mice and wild-type littermates in the locomotor activity and stereotyped behaviors induced by repeated cocaine administration. These findings demonstrate that dopamine D(3) receptors are not necessary for the acute NT mRNA response to drugs of abuse and antipsychotics but appear to play a role in the regulation of NT gene induction in striatal neurons after repeated cocaine. In addition, our results indicate that the acute locomotor response to cocaine and development of psychostimulant-induced behavioral sensitization do not require functional D(3) receptors.

Selective antagonism of nigral neuropeptide responses to methamphetamine by conantokin G, a naturally occurring conopeptide.

Some conopeptides derived from cone snails act on specific subunits of the NMDA receptor and thus, exert an influence on the dopamine system. In this study, one such conopeptide, conantokin G, was administered i.c.v. in conjunction with methamphetamine, a potent central nervous system stimulant known to cause dopamine release and changes in tissue levels of neurotensin and dynorphin A in some brain structures. Both single and multiple administrations of the conantokin G preferentially attenuated the methamphetamine-induced increases in tissue levels of these neuropeptides in the substantia nigra. Conantokin G also enhanced the behavioral effects of the methamphetamine.

Clozapine and haloperidol block the induction of behavioral sensitization to amphetamine and associated genomic responses in rats.

Behavioral sensitization resulting from repeated, intermittent exposure to psychostimulants such as amphetamine (Amp) is hypothesized to model pathophysiology of psychotic disorders. The present study was designed to characterize the effects of a typical and an atypical antipsychotic drug, haloperidol and clozapine, respectively, on the induction of context-independent sensitization to Amp. Peripheral Amp treatment for five days (2 mg/kg/day, s.c.) produced an augmented stimulant response to an acute Amp challenge (2 mg/kg, s.c.) given seven days after the last pretreatment injection. Interestingly, preexposure to high doses of either clozapine (20 mg/kg) or haloperidol (0.5 mg/kg) alone also led to a sensitized behavioral response to an acute Amp challenge. The cross-sensitization between Amp and high doses of the haloperidol and clozapine may have occluded any blockade of Amp behavioral sensitization by the antipsychotics. Indeed, administration of a lower dose of clozapine (4 mg/kg) or haloperidol (0.1 mg/kg) with Amp during the preexposure phase clearly blocked the induction of behavioral sensitization. In addition to the behavioral sensitization, Amp-pretreated rats showed a reduction in the ability of the acute Amp challenge to induce c-fos mRNA in the medial prefrontal cortex and neurotensin/neuromedin N (NT/N) mRNA in the nucleus accumbens-shell. At doses that blocked the initiation of behavioral sensitization to Amp, clozapine fully and haloperidol partially restored the capacity of acute Amp to induce c-fos and NT/N gene expression. These data lend support to the psychostimulant-sensitization model of psychosis and a role of dopamine D2-like receptors in the phenomenon.

Inhibition of neurotensin-stimulated mast cell secretion and carboxypeptidase A activity by the peptide inhibitor of carboxypeptidase A and neurotensin-receptor antagonist SR 48692.

BACKGROUND: Neurotensin (NT), a peptide found in brain and several peripheral tissues, is a potent stimulus for mast cell secretion and its actions are blocked by the specific NT receptor antagonist, SR 48692. Subsequent to stimulation, NT is rapidly degraded by mast cell carboxypeptidase A (CPA). In the experiments described here, we tested for the involvement of CPA activity in the activation of mast cell secretion by the peptide, NT. METHODS: Mast cells were isolated from the peritoneal and pleural cavities of rats, purified over metrizamide gradients and incubated at 37 degrees C in Locke solution or Locke containing the appropriate inhibitors. For some experiments, media derived from mast cells stimulated by compound 48/80 were used as a source of mast cell CPA activity. RESULTS: Treatment of mast cells with the highly specific peptide inhibitor of CPA derived from potato (PCI) inhibited histamine release in response to NT and NT8-13 (the biologically active region of NT). This inhibition required some 20 min to develop and was only partially reversed by a 20-min wash period. PCI (10 microM) did not inhibit histamine release in response to NT1-12, bradykinin, compound 48/80, the calcium ionophore, A23187, or anti-IgE serum. PCI also inhibited mast cell CPA activity. SR 48692, a highly selective antagonist of the brain NT receptor and of NT-stimulated mast cell secretion, also inhibited mast cell CPA activity as well as bovine pancreatic CPA activity in a concentration-dependent manner. DISCUSSION: It is suggested that the mast cell binding site for NT and the active site for CPA may share similar characteristics. The results are discussed in terms of NT mechanism of action on the mast cell.

Haloperidol regulates neurotensin gene expression in striatum of c-fos-deficient mice.

The immediate-early gene c-fos has been proposed to play a role in induction of neurotensin/neuromedin N (NT/N) gene expression in the striatum following acute haloperidol (HAL) treatment. We utilized mice with targeted disruption of the c-fos gene to directly test this hypothesis. A robust increase in NT/N gene expression was observed in the dorsolateral striatum (DLSt) in both wild-type (WT) and c-fos-deficient mice 4-6 h after a single injection of HAL (1 or 4 mg/kg) indicating that products of the c-fos gene are not absolutely required for induction of NT/N mRNA. The basal expression of preprotachykinin, preproenkephalin and preprocholecystokinin mRNAs did not differ between WT and c-fos knockout mice. HAL treatment first increased striatal NT/N mRNA on postnatal day (PD) 10. HAL-induced NT/N mRNA levels were significantly lower in c-fos knockout mice than in WT mice on PD 10 and 15. These findings indicate that reliance on c-fos may be greater earlier in development and that redundant molecular pathways can lead to induction of NT/N mRNA in mouse striatum.

Comparison of neurotensin responses to MDL 100,907, a selective 5HT2A antagonist, with clozapine and haloperidol.

The unique pharmacological profile of atypical antipsychotics, such as clozapine, suggests that action on non-dopaminergic transmitter systems might contribute to the unique therapeutic benefits of these drugs. In order to test this possibility, the response of neurotensin systems to drugs with antipsychotic potential was examined because of this peptide's putative association with psychiatric disorders. The effects of treatments by haloperidol, clozapine, and MDL 100,907 (a selective 5HT2A antagonist thought to have antipsychotic activity) on NT pathways were determined in various extrapyramidal and limbic regions and compared. The response of neurotensin systems was determined by measuring neurotensin-like immunoreactivity after 1, 2, 4, and 5 drug administrations. It was observed that tissue content of this peptide in caudate and nucleus accumbens regions tended to be elevated after 1 or 2 drug administrations, but had either returned or was returning to control levels after 4 or 5 drug administrations. In general, the extrapyramidal and limbic neurotensin levels responded in a similar manner to clozapine and the 5HT2A antagonist, but differently for haloperidol in most regions examined. An important exception was in the nucleus accumbens, where all three drugs had similar effects on neurotensin tissue levels. These results suggest that 5HT2A receptors exert basal control over some extrapyramidal and limbic neurotensin systems and this interaction might contribute to the antipsychotic effects of these drugs.

Bowel resection and neurotensin treatment. Histochemical study of neurotensin-like and somatostatin-like immunoreactivities and receptors.

The influence of a bowel-trophic neurotensin (NT) treatment (13 days, 300 micrograms/kg/every 12 hrs.) on neurotensin-like immunopositive structures (neurons, fibres and epithelial-N-cells) and the neurotensin receptors (NTr) in the residual bowel after resection (90% small bowel or 75% colon) in the rat was studied using histochemical methods. Somatostatin-like (ST) immunopositive structures (neurons, fibres and epithelial-D-cells) and somatostatin receptors (STr) were also studied, comparatively. The results displayed a general increase of N-cells (11-17%) but not of D-cells, and a higher degree of variability section-to-section in the NT and ST immunopositive nervous structures (without increased density) after both resections, both with or without NT treatment. Receptors did not change after the small bowel resection but the colon resection and/or the NT treatment produced variations in the NT binding (from -24.3 to +16.85) in different intestinal regions. In a general sense, the variations among 1) the controls, 2) the resected animals, and 3) the resected and NT-treated animals, were of less extent (< or = 24%) than previously supposed for explaining the trophic effect of NT. Our results: a) confirm the autonomy, injury-resistance and tendency to maintain the physiological features of the bowel in very diverse situations; b) open new questions on both, the neurotensinergic changes after bowel resection and the mechanisms of the trophic effect of NT treatment, and c) suggest that, when neurotensin was applied as a trophic treatment in the cases of the need of a bowel resection, no important neurotensinergic or somatostatinergic side effects should be expected in the remaining bowel. However, the higher degree of variability section-to-section after surgery in the nervous structures was not modified by the NT treatment. This fact, and the different response of various intestinal regions to the NT treatment, suggest that functional problems in the remaining bowel could be maintained despite the growth of the mucosa induced by the NT treatment.

Chronic haloperidol-induced changes in regional dopamine release and metabolism and neurotensin content in rats.

Chronic neuroleptic administration has previously been shown to alter in vivo measures of dopaminergic function and lead to regionally selective increases in neurotensin levels. In the current study, female rats were administered chronic haloperidol for 6 months via subcutaneous silastic implants. After 24 weeks of administration, microdialysis probes were inserted into the lateral caudate putamen and the medial prefrontal cortex. Basal samples were collected prior to infusion of a high K+ concentration (100 mM KCl). Extracellular concentrations of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid were assessed using HPLC. Chronic haloperidol-treated rats showed increased basal dopamine metabolite levels in the caudate putamen and an altered response to the effects of high K+ on 3,4-dihydroxyphenylacetic acid; no significant differences were seen with other analytes in the caudate putamen. Although basal concentrations were not different between groups in the prefrontal cortex, haloperidol-treated rats showed a significant attenuation of response to the effects of high K+ infusion on dopamine metabolite concentrations. Radioimmunoassay measurement of tissue neurotensin content showed highly significant elevations of neurotensin concentrations in the caudate putamen and nucleus accumbens, but not in other brain regions analyzed. These results suggest a confluence of altered dopamine and neurotensin function in the caudate putamen which may be related to motor side effects of haloperidol, whereas changes in prefrontal dopamine function are not associated with altered neurotensin levels.

PC12 cells can be induced to produce, but do not process, the neurotensin/neuromedin N precursor.

Neurotensin and neuromedin N are two biologically active, related peptides that are encoded in the same precursor molecule. In the rat, the precursor consists of a 169-residue polypeptide containing in its C-terminal region one copy each of neurotensin and neuromedin N. Four Lys-Arg sequences, which are thought to represent putative processing sites, occur in the precursor molecule. Studies by others have shown that rat pheochromocytoma PC12 cells produced neurotensin and dramatically increased their neurotensin/neuromedin N precursor mRNA content in response to a combination of nerve growth factor, dexamethasone, forskolin, and Li+. Here, we investigated the effects of this combination of inducers on the posttranslational processing of the neurotensin/neuromedin N precursor in PC12 cells. Radioimmunoassays coupled to HPLC and arginine-directed tryptic cleavage of cell extracts were performed with five antisera specific for precursor sequences adjacent to basic doublets. Thus, mature neurotensin and neuromedin N represented less than 1% of the total precursor content in PC12 cells. The PC12 cell line may represent an interesting model with which one could transfect the recently cloned prohormone convertases PC1 and PC2, thereby allowing the study of the role of these enzymes in the processing of the neurotensin/neuromedin N precursor.

Specificity and mode of action of the muscle-type protein-arginine deiminase.

The primary and secondary specificities and mode of action of the muscle-type protein-arginine deiminase (PAD) were investigated using various derivatives of Arg and its homologues, as well as Arg-containing peptides by quantitative analyses of the reaction products on reverse-phase HPLC. The enzyme converted benzoyl-D-Arg-p-nitroanilide into its citrulline derivative at 18% of the rate of the L-isomer, while the D-Arg residues in peptides were not deiminated to a significant extent. This suggests that PAD does not have strict stereospecificity and it is dependent on the structure of the residues or groups on both sides of the target Arg residue. In contrast, the benzoyl-/-ethyl ester derivatives of homoarginine, alpha-amino-beta-guanidino-propionic acid, canavanine, and NG-methyl-Arg, exhibited poor PAD susceptibility, suggesting that the length and nature of the arm as exactly three CH2 groups, and the integrity of the guanidyl group are quite strict specificity determinants. The enzyme action on Arg residues in peptides depends greatly on their position in the sequence, and on the nature of the neighboring residues. For example, deimination of Arg residues situated at positions 1-3 from the NH2-terminus, except for those preceded by a carbobenzoxy- or benzoyl-group, were in most cases very slow, whereas those at the COOH-terminus were deiminated relatively faster. A single Arg residue sandwiched between two Pro residues was not deiminated at all, while a pair of Arg residues between two Pro were deiminated moderately. Consequently, PAD exhibited a variety of modes of action on more than one Arg residues in the peptides tested. The results suggest the applicability of PAD, albeit quite limited, for selective modification of certain Arg residues in peptides and proteins by appropriately controlling reaction time and several other parameters. The PAD's mode of action was compared with those of three Arg-bond cleaving proteases.

[Effect of interleukins and somatomedins on the production of neurotensin by cell line SH-SY5Y derived from human neuroblastoma]. / Effet des interleukines et des somatomédines sur la production de neurotensine par la lignée cellulaire SH-SY5Y dérivée d'un neuroblastome humain.

The goal of this study was to investigate the regulation by insulin-like growth factors 1 and 2, and interleukins on the production of neurotensin in the SH-SY5Y cell line derived from a human neuroblastoma. Cultures were performed in RPMI1640 culture medium with heated foetal calf serum 12%. After 24 hrs. of fasting without serum, interleukins-1 alpha, IL-2, IL-4 and insulin-like growth factors 1 and 2 were added. Results showed: 1) A mitogenic effect of ILs (p < 0.001) and of IGFs (p < 0.001). 2) The presence of neurotensin in HCl0.1N cellular extracts (0.06 fmol/micrograms protein). 3) The increase of cellular neurotensin content in the presence of IL-4 (560%), IL-2 (480%), IGF-1 (610%) and IGF-2 (200%). Our results indicate that the human neuroblastoma cell line SH-SY5Y produces neurotensin and that ILs and IGFs act in vitro to modulate this production.