Short communication: malic acid does not promote vaccenic acid accumulation in mixed ruminal fluid with fractionated fish oil by a rumen-simulation technique

The objective of this study was to determine whether malic acid could promote the accumulation of vaccenic acid in the rumen. The control diet was composed of a 65:35 ratio of forage to concentrate with 1% (dry matter basis) added fractionated fish oil (rich in docosahexaenoic acid), and treatment diets consisted of the control diet with added malic acid to achieve final concentrations of 10 mM (treatment 1) and 20 mM (treatment 2), respectively. The experiment was conducted with rumen-simulation equipment (Rusitec) consisting of 9 fermenters. Each treatment included 3 fermenters as replicates. After 7 d of incubation, concentrations of vaccenic acid from treatment 1 (4.38% fatty acids) and treatment 2 (4.46% fatty acids) were similar to that of the control treatment (4.51% fatty acids). The disappearance of docosahexaenoic acid was not different among the control, treatment 1, or treatment 2. These data indicated that malic acid did not promote the accumulation of vaccenic acid in ruminal fluid.

The effect of implanting an antigen release device on lactoferrin concentration in serum and milk

The objective of this study was to evaluate the effect of implanting an Antigen Release Devices (ARD) into dairy cows during the lactation cycle to induce an immune response. Subsequently, the concentrations of lactoferrin in serum and milk were measured. Forty healthy adult Chinese Holstein cows were divided into two equal groups: a test group and a control group. Animals in the test group received ARD implants, whereas the control group animals were not treated. An even spread across the two groups was maintained with animal selection based on parity, the lactation days and milk yields. The concentrations of lactoferrin in the serum and milk of all forty animals were measured using an Enzyme-Linked Immunosorbent Assay (ELISA). The results show that the implantation of an ARD did not significantly increase the concentration of lactoferrin in the serum and milk throughout the whole experiment period except on two occasions. The levels of lactoferrin in the milk and serum significantly increased on day 7 and on day 11 after implantation (p<0.05). There was a strong correlation between milk lactoferrin and serum lactoferrin (r=0.564, P<0.01). Three separate ARDs were used releasing its antigen load on day 0, 14 and 28 to induce a primary, secondary and tertiary response respectively. As the significant increases in the lactoferrin levels were only observed after the first ARD release, the effects of lactoferrin appears to be associated with the early phase of the immune response, consistent with its role in the host's innate defense system.

Modulation of AMPA receptor GluR1 subunit phosphorylation in neurons by the intravenous anaesthetic propofol

BACKGROUND

The ionotropic glutamate receptor is a potential molecular site in the central nervous system that general anaesthetics may interact with to produce some of their biological actions. Protein phosphorylation has been well documented to occur in the intracellular C-terminal domain of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) subtype of glutamate receptors, which represents a pivotal mechanism for the post-translational modulation of AMPA receptor functions. In this study, we investigated a possible influence of an i.v. anaesthetic agent propofol on the phosphorylation of AMPA receptor GluR1 subunits in cultured neurons.

METHODS

The effect of propofol on phosphorylation of GluR1 subunits at serine 831 and 845 was assayed in cultured rat striatal and cortical neurons by western blot with phospho- and site-specific antibodies.

RESULTS

Propofol consistently elevated phosphorylation of GluR1 subunits at the C-terminal serine 845 site in both striatal and cortical neurons. The elevation in phosphorylation was concentration-dependent and started at a low concentration (3 microM). This increase in serine 845 phosphorylation was rapid and sustained during the entire course of propofol exposure. In contrast to serine 845, phosphorylation of GluR1 at serine 831 was not altered by propofol in striatal and cortical neurons. Total GluR1 abundance remained unchanged in response to propofol incubation.

CONCLUSIONS

These data indicate that propofol possesses the ability to upregulate AMPA receptor GluR1 subunit phosphorylation at a specific serine 845 site in neurons and provide evidence supporting the AMPA receptor as a molecular target for general anaesthetics.

Factors affecting the lactoferrin concentration in bovine milk

Lactoferrin (LF) concentrations in the milk with different levels of the somatic cell count score were examined using an ELISA to determine whether milk LF concentration is influenced by parity of the cow, stage of lactation, and the somatic cell count. The study animals were 198 Chinese Holstein cows randomly chosen from more than 1,600 cows in 4 dairy farms in the Beijing area. The cows had shown no sign of mastitis for 2 mo. Daily milk production was recorded, and milk samples were taken from individual cow samples. The LF concentration varied between 31.78 and 485.63 microg/mL in milk from normal animals. Lactoferrin was significantly associated with stage of lactation (r = 0.557) and daily milk production (r = -0.472). Nevertheless, there was no significant relationship with parity. Moreover, milk LF concentration tended to be correlated with the somatic cell count score (r = 0.375). This finding suggests that milk LF may be helpful as an indicator for intramammary infection in dairy cows.

Study of drug resistance among 78 antiretroviral treatment-naive patients with HIV-1 subtype B infection in central China

To study the prevalence of drug resistance mutations among HAART (highly active anti-retroviral therapy) naive subjects with HIV-1 subtype B infection, evaluate the correlation between major mutations and viral loads. Additionally, to investigate the primary resistance spectrum in the central plains of China and provide some guidance for the choice of antiretroviral drugs (ARV). Drug resistance mutations and viral loads were measured in 78 treatment-naïve patients with HIV infection and the results were analyzed with descriptive statistical and multiple statistical analysis. The most common mutations were L63P, V77I and I93L, which belong to minor mutations of the proteinase gene, and none of which had any relation to viral loads. The major mutations, which were mainly K103N and Q151M, were less frequent in China than those in other countries. There was a certain correlation between viral loads and I93IL according to stepwise regression analysis. The incidence of primary mutations among HAART naïve patients was lower in China's central plains than that in other countries, and the most common mutations had no relation to viral loads. Though major mutations affecting choice of ARV are not common in China, they deserve further attention.

Characterization of a reference material for BCR-ABL (M-BCR) mRNA quantitation by real-time amplification assays: towards new standards for gene expression measurements

Monitoring of BCR-ABL transcripts has become established practice in the management of chronic myeloid leukemia. However, nucleic acid amplification techniques are prone to variations which limit the reliability of real-time quantitative PCR (RQ-PCR) for clinical decision making, highlighting the need for standardization of assays and reporting of minimal residual disease (MRD) data. We evaluated a lyophilized preparation of a leukemic cell line (K562) as a potential quality control reagent. This was found to be relatively stable, yielding comparable respective levels of ABL, GUS and BCR-ABL transcripts as determined by RQ-PCR before and after accelerated degradation experiments as well as following 5 years storage at -20 degrees C. Vials of freeze-dried cells were sent at ambient temperature to 22 laboratories on four continents, with RQ-PCR analyses detecting BCR-ABL transcripts at levels comparable to those observed in primary patient samples. Our results suggest that freeze-dried cells can be used as quality control reagents with a range of analytical instrumentations and could enable the development of urgently needed international standards simulating clinically relevant levels of MRD.

Effectiveness of oils rich in linoleic and linolenic acids to enhance conjugated linoleic acid in milk from dairy cows

Forty Holstein dairy cows were used to determine the effectiveness of linoleic or linolenic-rich oils to enhance C18:2 cis-9, trans-11 conjugated linoleic acid (CLA) and C18:1 trans-11 (vaccenic acid; VA) in milk. The experimental design was a complete randomized design for 9 wk with measurements made during the last 6 wk. Cows were fed a basal diet containing 59% forage (control) or a basal diet supplemented with either 4% soybean oil (SO), 4% flaxseed oil (FO), or 2% soybean oil plus 2% flaxseed oil (SFO) on a dry matter basis. Total fatty acids in the diet were 3.27, 7.47, 7.61, and 7.50 g/100 g in control, SO, FO, and SFO diets, respectively. Feed intake, energy-corrected milk (ECM) yield, and ECM produced/kg of feed intake were similar among treatments. The proportions of VA were increased by 318, 105, and 206% in milk fat from cows in the SO, FO, and SFO groups compared with cows in the control group. Similar increases in C18:2 cis-9, trans-11 CLA were 273, 150, and 183% in SO, FO, and SFO treatments, respectively. Under similar feeding conditions, oils rich in linoleic acid (soybean oil) were more effective in enhancing VA and C18:2 cis-9, trans-11 CLA in milk fat than oils containing linolenic acid (flaxseed oil) in dairy cows fed high-forage diets (59% forage). The effects of mixing linoleic and linolenic acids (50:50) on enhancing VA and C18:2 cis-9, trans-11 CLA were additive, but not greater than when fed separately. Increasing the proportion of healthy fatty acids (VA and CLA) by feeding soybean or flaxseed oil would result in milk with higher nutritive and therapeutic value.

Cocaine increases endoplasmic reticulum stress protein expression in striatal neurons

Cocaine administration upregulates the levels of extracellular glutamate and dopamine in the striatum. Activation of the receptors alters calcium homeostasis in striatal neurons leading to the expression of the endoplasmic reticulum (ER) stress proteins. It was therefore hypothesized that cocaine upregulates the expression of the ER stress proteins, immunoglobulin heavy chain binding protein (BiP), Ire1alpha and perk via glutamate and dopamine receptor activation. A novel glutamate microbiosensor and Western immunoblot analyses were mainly performed to test the hypothesis in the rat dorsal striatum. The results showed that i.p. injection of repeated cocaine (20 mg/kg) for nine consecutive days significantly increased extracellular glutamate levels while acute cocaine injection did not. However, the immunoreactivities (IR) of the ER stress proteins in the dorsal striatum were significantly increased by either acute or repeated cocaine injections as compared with saline controls. Intrastriatal injection (i.s.) of the selective group I metabotropic glutamate receptor (mGluR) antagonist N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC; 25 nmol) or the mGluR5 subtype antagonist 2-methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP; 2 and 25 nmol) significantly decreased repeated cocaine-induced increases in the IR of the ER stress proteins in the injected dorsal striatum. Similarly, the selective D1 antagonist (R)-(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH23390; 0.1 mg/kg, i.p.) or the N-methyl-d-aspartate antagonist dizocilpine/(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-ibenzo[a,d]cyclohepten-5,10-imine maleate (MK801; 2 nmol, i.s.) decreased acute or repeated cocaine-induced the IR of the ER stress proteins in the dorsal striatum. These data suggest that cocaine upregulates expression of the ER stress proteins in striatal neurons via a mechanism involving activation of glutamate and dopamine receptors.

Cardiovascular responses to microinjection of nociceptin and endomorphin-1 into the nucleus tractus solitarii in conscious rats

Increasing evidence suggests an active participation of nociceptinergic transmission in the central control of cardiovascular activity and reflex. In this study, the role of the classic opioid mu receptor and the nociceptin/orphanin FQ receptor, a novel opioid receptor, in the nucleus tractus solitarii (NTS) in the regulation of cardiovascular activity was investigated and compared in chronically cannulated and freely moving conscious rats. Microinjections of nociceptin, an endogenous ligand for the nociceptin receptor, into the relatively rostral NTS produced dose-related (0.04, 0.2, and 1 nmol) increases in blood pressure and heart rate. Intra-NTS injection of the selective nociceptin receptor antagonist [Nphe(1)]Nociceptin(1-13)NH(2) (NOR-AN) at 1 nmol blocked the increases in blood pressure and heart rate induced by nociceptin. In contrast, pretreatment with the nonselective opioid receptor antagonist naloxone (5 nmol) had no effects on the cardiovascular responses to nociceptin. Like nociceptin, microinjection of endomorphin-1 (EM-1), an endogenous ligand for the opioid mu receptor, into the rostral NTS increased blood pressure and heart rate in a dose-dependent manner (0.04, 0.2, and 1 nmol). Pretreatment with naloxone (5 nmol), but not NOR-AN, blocked cardiovascular responses elicited by EM-1. Neither NOR-AN nor naloxone alone had significant effects on the baseline blood pressure and heart rate. Injection of excitatory amino acid l-glutamate (1 nmol) into the same sites caused the typical depressor and bradycardic responses. In the caudal NTS areas, nociceptin and EM-1 seemed to induce opposite responses: hypotension and bradycardia. These results suggest that the novel nociceptin receptors and traditional opioid receptors in the NTS may be independently involved in the regulation of cardiovascular activity.

Interactions between ionotropic and metabotropic glutamate receptors regulate cAMP response element-binding protein phosphorylation in cultured striatal neurons

The striatum is a key structure of basal ganglia controlling extrapyramidal motor activity and processing addictive plasticity of abused substances. Glutamatergic transmission that is enriched in the striatum regulates a variety of striatal neuronal activities via selective activation of ionotropic and metabotropic glutamate receptors (mGluRs). In this study, the interaction between N-methyl-D-aspartate (NMDA) receptors and group I mGluRs (mGluR1 and mGluR5 subtypes) in activating a phosphorylation cascade to a transcription factor cAMP response element-binding protein (CREB) was investigated in primary cultures of E18 or postnatal day 1 striatal neurons. We found that activation of NMDA receptors with NMDA rapidly and concentration-dependently increased the number of neurons expressing phosphorylated CREB (pCREB) as revealed by immunocytochemistry. The increased pCREB expression by NMDA was sensitive to an NMDA antagonist MK801. Co-incubation of a subthreshold dose of a group I mGluR agonist 3,5-dihydroxyphenylglycine (DHPG) that itself did not alter basal pCREB expression augmented NMDA-induced CREB phosphorylation. The mGluR5 antagonist 2-methyl-6-(phenylethynyl)pyridine hydrochloride blocked the DHPG augmentation of NMDA-induced CREB phosphorylation, while the mGluR1 antagonist 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester did not. Interestingly, the protein kinase C inhibitors chelerythrine and Gö6983 also prevented DHPG from enhancing CREB phosphorylation induced by NMDA. Whereas a low dose of the protein kinase C activator phorbol 12-myristate 13-acetate mimicked the DHPG potentiation. These results indicate a facilitatory regulation of an NMDA cascade to CREB phosphorylation by concurrent glutamatergic tone on mGluR5, which is probably processed via an intracellular signaling pathway involving protein kinase C.

Regulation of transcription factor phosphorylation by metabotropic glutamate receptor-associated signaling pathways in rat striatal neurons

The group I metabotropic glutamate receptors (mGluRs) are positively coupled to phospholipase C. Through phospholipase C, group I mGluR activation increases intracellular concentrations of diacylglycerol which is known as a strong activator of protein kinase C (PKC). This study investigated the putative role of PKC in the regulation of transcription factor phosphorylation induced by group I mGluR activation in the rat striatum in vivo. We found that the group I agonist 3,5-dihydroxyphenylglycine (DHPG) injected into the dorsal striatum (caudate-putamen) increased phosphorylation of the two transcription factors, cAMP response element-binding protein (CREB) and Elk-1, and extracellular signal-regulated kinase 1/2 (ERK1/2) in the injected striatum. Inhibition of PKC with GF109203X significantly attenuated DHPG-stimulated CREB, Elk-1, and ERK1/2 phosphorylation. Activation of PKC with intracaudate injection of 12-O-tetradecanoylphorbol-13-acetate (TPA) mimicked DHPG actions in facilitating the phosphorylation of CREB, Elk-1, and ERK1/2. Blockade of N-methyl-D-aspartate (NMDA) glutamate receptors with the non-competitive antagonist MK801 or the competitive antagonist AP5 attenuated TPA-induced CREB, Elk-1, and ERK1/2 phosphorylation. Similarly, inhibition of Ca(2+)/calmodulin-dependent protein kinases (CaMK) with KN62 also resulted in a significant attenuation of TPA induction of the three phosphoproteins. The data obtained from this study indicate that selective activation of PKC is needed for the group I agonist-induced CREB, Elk-1, and ERK1/2 phosphorylation in striatal neurons. Activated PKC may, at least in part, facilitate the phosphorylation of transcription factors via an NMDA/CaMK-sensitive pathway.

A comparison of international references for the assessment of child and adolescent overweight and obesity in different populations

OBJECTIVE

To compare different references assessing child and adolescent overweight and obesity in different populations.

DESIGN

Comparison cross-sectional study.

SETTING

The United States, Russia, China.

SUBJECTS

A total of 6108 American, 6883 Russian and 3014 Chinese children aged 6-18 y.

INVESTIGATION

Using nationwide survey data from the USA (NHANES III, 1988-1994), Russia (1992), and China (1991), we compared three references: (1) the International Obesity Task Force (IOTF) reference, sex-age-specific body mass index (BMI) cut-offs that correspond to BMIs of 25 for overweight and 30 for obesity at age 18; (2) the World Health Organization (WHO) reference--BMI 85th percentiles for overweight in adolescents (10-19 y) and weight-for-height Z-scores for obesity in children under 10; (3) a USA reference--BMI 85th and 95th percentiles to classify overweight and obesity, respectively.

RESULTS

Using the IOTF reference and 85th BMI percentiles, overweight prevalence was 6.4 and 6.5% in China, 15.7 and 15.0% in Russia, and 25.5 and 24.4% in the USA, respectively. Notable differences existed for several ages. Kappa (=0.84-0.98) indicated an excellent agreement between the two references in general, although they varied by sex-age groupings and countries. Overweight prevalence was twice as high in children (6-9 y) than in adolescents (10-18 y) in China and Russia, but was similar in the USA. Estimates of obesity prevalence using these three references varied substantially.

CONCLUSIONS

The references examined produce similar estimates of overall overweight prevalence but different estimates for obesity. One should be cautious when comparing results based on different references.

SPONSORSHIP

University of Illinois and University of North Carolina.

Augmented motor activity and reduced striatal preprodynorphin mRNA induction in response to acute amphetamine administration in metabotropic glutamate receptor 1 knockout mice

Metabotropic glutamate receptor 1 (mGluR1) is a G-protein-coupled receptor and is expressed in the medium spiny projection neurons of mouse striatum. To define the role of mGluR1 in actions of psychostimulant, we compared both motor behavior and striatal neuropeptide mRNA expression between mGluR1 mutant and wild-type control mice after a single injection of amphetamine. We found that acute amphetamine injection increased motor activity in both mutant and control mice in a dose-dependent manner (1, 4, and 12 mg/kg, i.p.). However, the overall motor responses of mGluR1 -/- mice to all three doses of amphetamine were significantly greater than those of wild-type +/+ mice. Amphetamine also induced a dose-dependent elevation of preprodynorphin mRNA in the dorsal and ventral striatum of mutant and wild-type mice as revealed by quantitative in situ hybridization. In contrast to behavioral responses, the induction of dynorphin mRNA in both the dorsal and ventral striatum of mutant mice was significantly less than that of wild-type mice in response to the two higher doses of amphetamine. In addition, amphetamine elevated basal levels of substance P mRNA in the dorsal and ventral striatum of mGluR1 mutant mice to a similar level as that of wild-type mice. There were no differences in basal levels and distribution patterns of the two mRNAs between the two genotypes of mice treated with saline. These results demonstrate a clear augmented behavioral response of mGluR1 knockout mice to acute amphetamine exposure that is closely correlated with reduced dynorphin mRNA induction in the same mice. It appears that an intact mGluR1 is specifically critical for full dynorphin induction, and impaired mobilization of inhibitory dynorphin system as a result of lacking mGluR1 may contribute to an augmentation of motor stimulation in response to acute administration of psychostimulant.

Profound astrogenesis in the striatum of adult mice following nigrostriatal dopaminergic lesion by repeated MPTP administration

Neural progenitor cells are present in the rodent brain throughout adulthood, and can proliferate and differentiate into new neurons and/or glia to repair injury. To explore the repair processes mediated by brain progenitor cells, a selective lesion of the nigrostriatal dopaminergic pathway was induced in young adult mice by repeated administration of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). A thymidine analog, bromodeoxyuridine (BrdU), was used as a tracer for DNA synthesis to label the dividing cells and their terminal progeny following injury. Three days after MPTP treatments (25 mg/kg, once daily for 5 days), an 8-fold increase in the number of BrdU-labeled newborn cells was observed in the dorsal striatum. A 5-fold increase was also seen in the substantia nigra (SN). Newborn cells in the striatum survived beyond 60 days after their birth whereas newborn cells in the SN survived for less than 31 days. The vast majority of newborn cells in the striatum differentiated into astroglia according to their radial morphology and co-expression with an astroglial marker, S100beta, within 10 days after birth. In contrast, most BrdU-positive cells in the SN failed to co-express S100beta. Little or none of BrdU-labeled cells in both the striatum and SN were found to co-localize with a neuronal marker, neuronal nuclear antigen, or tyrosine hydroxylase during the full course of survival days surveyed (3 to 60 days). Repeated MPTP also decreased dopamine content and uptake in the striatum, which showed a significant recovery 31 days after MPTP lesion. These results demonstrate a rapid and profound astrogenesis in the striatum of young adult mice in response to toxic dopaminergic insult. The lack of neurogenesis in the two affected brain areas indicates the relative importance of glial cell regeneration in repairing MPTP injury.

Group I metabotropic glutamate receptors control phosphorylation of CREB, Elk-1 and ERK via a CaMKII-dependent pathway in rat striatum

In vivo activation of group I metabotropic glutamate receptors (mGluRs) upregulates phosphorylation of cyclic AMP response element-binding protein (CREB), Elk-1 and extracellular signal-regulated kinases (ERK) in striatal neurons. To evaluate putative roles of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in CREB, Elk-1 and ERK phosphorylation, the CaMKII inhibitor, KN62, was infused simultaneously with the group I mGluR agonist, 3,5-dihydroxyphenylglycine (DHPG), into the rat dorsal striatum. The results showed that DHPG (125, 250, and 500 nmol) increased phosphorylated (p) CaMKII immunoreactivity (IR) in a dose-dependent manner. KN62 (50 nmol) significantly attenuated 500 nmol DHPG-induced pERK, pElk-1 and pCREB IR in the ipsilateral dorsal striatum. These data indicate that pCaMKII is a possible upstream effector that is responsible for the regulation of CREB, Elk-1 and ERK phosphoproteins in response to group I mGluR stimulation in striatal neurons.

[Non-linear compression for noises in non-contact vital signs detecting system]

A method for compressing the noises overlapping in the breath and heart signals of human beings, detected by the non-contact vital signs detecting system during the display of the waveforms in time domain, is discussed in this paper in detail. And what's more, the problem that the noise level is changed along with the increase of the gain of AD data-acquisition card and the display--gain of the software is solved by researching into the threshold of noise-level contraction in two types of circumstance in the lab, and the result of the breath and heart signal in the condition of lower noise is realized as well.

Group I metabotropic glutamate receptor activation increases phosphorylation of cAMP response element-binding protein, Elk-1, and extracellular signal-regulated kinases in rat dorsal striatum

Cyclic AMP response element-binding protein (CREB) is a major transcriptional activator at the calcium and cAMP response-element (CaCRE). Phosphorylated (p)CREB facilitates gene expression in striatal neurons. Elk-1 is another transcriptional regulator at the serum response element in the upstream promoter region of the CaCRE. Elk-1 is phosphorylated by extracellular signal-regulated kinases (ERK) and may also contribute to the regulation of gene expression. To evaluate putative roles of group I metabotropic glutamate receptors (mGluRs) in CREB, Elk-1, and ERK phosphorylation, the group I selective agonist, 3,5-dihydroxyphenylglycine (DHPG), was infused into the dorsal striatum at doses of 125, 250, or 500 nmol in freely moving rats. Semi-quantitative immunohistochemistry demonstrated that DHPG significantly increased levels of pCREB, pElk-1, and pERK immunoreactivity of ipsilateral dorsal striatum in a dose dependent manner. The increased immunoreactivity by 500 nmol DHPG was significantly blocked by intrastriatal infusion of the group I selective antagonist, n-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC, 25 nmol), but not by the group II/III antagonist, (RS)-alpha-methylserine-o-phosphate monophenyl ester (MSOPPE, 25 nmol). These data suggest that group I mGluR activation is positively linked to signaling cascades resulting in CREB, Elk-1, and ERK phosphorylation in the striatum in vivo.

[Angiotensin II in rostral ventrolateral medulla mediates amino acids release from spinally projecting nerve terminals in the spinal cord]

Microdialysis in the intermediolateral column (IML) was employed to examine amino acids release induced by angiotensin II (ANG II) applied into the rostral ventrolateral medulla (RVLM). Microinjection of ANG II (100 pmol, n = 11) into the RVLM significantly increased (P < 0.01) the release of aspartate (from 4.75 +/- 1.01 to 8.90 +/- 2.28 pmol/20 microliters) and glutamate (from 18.99 +/- 8.64 to 73.88 +/- 29.26 pmol/20 microliters) in the spinal cord. The increase of glutamate release was significantly attenuated (P < 0.05) by pretreatment with losartan (10 nmol, n = 8) at the same RVLM site. Immunofluorescence double labeling combined with confocal microscopic observation demonstrated that 62%-91% of the glutamatergic neurons in the RVLM were double-labeled with AT1 receptors, supporting the view that ANG II-induced glutamate release in the spinal cord may arise from the AT1 receptor-containing glutamatergic spinally projecting neurons in the RVLM.

Gliogenesis in the striatum of the adult rat: alteration in neural progenitor population after psychostimulant exposure

Cytogenesis from proliferating progenitor cells is present in the rat brain throughout adulthood, and is regulated by a variety of environmental stimuli. To determine whether adult cytogenesis occurs in the intact rat striatum and to explore the possible regulatory role of psychostimulant exposure on striatal cytogenesis, immunohistochemistry with the thymidine analog bromodeoxyuridine (BrdU), a marker of DNA synthesis that labels dividing cells and their terminal progeny, was performed on the brain sections of normal adult rats and rats treated with a psychostimulant, amphetamine (AMPH). Scattered cells that incorporated BrdU were consistently seen throughout the dorsal (caudate putamen) and ventral (nucleus accumbens) striatum 24 h after BrdU injection. Three to four weeks after BrdU injection, approximately 10-20% of surviving newborn cells differentiated into astroglia according to their radial morphology of glia and co-expression of an astroglial marker, S100beta. However, none of BrdU-positive cells were found to co-localize with a neuronal marker, neuronal nuclear antigen (NeuN). Acute injection of AMPH at a behaviorally active dose (10 mg/kg, i.p.) produced a rapid and transient decrease in the number of BrdU-labeled cells in both the dorsal (70.6% of control) and ventral (66.7% of control) striatum, but not in the subventricular zone and the hippocampal dentate gyrus. However, the fraction of differentiated astrocytes was not altered 3-4 weeks after AMPH treatment. These results indicate an existence of active gliogenesis (both proliferation and differentiation) in the adult rat striatum. Vulnerability of striatal cytogenesis to psychostimulant exposure indicates a new approach to elucidate brain mechanisms responsible for addictive properties of drugs of abuse.

Dose-related alteration in nitric oxide synthase mRNA expression induced by amphetamine and the full D1 dopamine receptor agonist SKF-82958 in mouse striatum

Neuronal nitric oxide synthase (nNOS) is normally expressed in one population of intrinsic interneurons of the striatum. Production of nitric oxide in the nNOS-containing neurons is sensitive to dopamine stimulation. Using quantitative in situ hybridization, the present study investigated the alteration in basal nNOS mRNA expression in striatal nNOS-containing neurons of mice treated with the psychostimulant amphetamine or a full D1 dopamine receptor agonist, SKF-82958. A single systemic injection of amphetamine induced a dose-related change in striatal nNOS mRNA expression. Whereas amphetamine at 4 mg/kg decreased basal levels of nNOS mRNA in both the dorsal (caudoputamen) and ventral (nucleus accumbens) striatum, the drug at a higher dose (12 mg/kg) increased nNOS expression in the two regions. Similarly, an acute systemic injection of SKF-82958 decreased and increased nNOS mRNA levels in the dorsal and ventral striatum at 2 and 4 mg/kg, respectively. These data indicate that constitutive nNOS expression in nitric oxide-producing neurons of the mouse striatum is regulated by dopaminergic transmission. Altered nNOS expression may result in changes in nitric oxide synthesis and thus contribute to biological actions of dopamine stimulants.

Differentially altered mGluR1 and mGluR5 mRNA expression in rat caudate nucleus and nucleus accumbens in the development and expression of behavioral sensitization to repeated amphetamine administration

Altered glutamatergic transmission in the striatum may be implicated in behavioral sensitization to repeated amphetamine (AMPH) administration. Quantitative in situ hybridization histochemistry was performed to define the effects of acute and chronic AMPH exposures on mRNA expression of Group I metabotropic glutamate receptors (mGluRs) in the striatum. Behavioral ratings indicated that the motor activity of rats was significantly higher after the final of five daily AMPH injections (4 mg/kg, i.p.) than that after the first of five daily AMPH, indicative of the development of behavioral sensitization. Moreover, the motor activity of rats treated with five daily AMPH was significantly greater than that of rats treated with five daily saline in response to a 2 mg/kg challenge dose of AMPH 7, 14, 28, and 60 days after the discontinuation of drug treatments, indicative of the persistent expression of behavioral sensitization. Three hours after acute administration of AMPH to naive rats, mGluR1 and mGluR5 mRNA expression in the dorsal (caudatoputamen) and ventral (nucleus accumbens) striatum showed no change as compared to acute saline injection. In rats that developed behavioral sensitization to repeated AMPH, mGluR1 levels in the dorsal and ventral striatum were increased by 53% and 43%, respectively, 3 h after the final AMPH treatment. However, this change did not persist during withdrawal since it was not observed 7, 14, and 28 days after the discontinuation of AMPH treatment. Conversely, mGluR5 levels were markedly reduced 3 h after the final of five daily AMPH treatments in the entire striatum of sensitized rats (34% and 77% of controls in the dorsal and ventral striatum, respectively). The reduction persisted at 7, 14, and 28 days of withdrawal. These results reveal a close linkage between striatal Group I mGluR gene expression and behavioral sensitization to AMPH. This may indicate functional implications of the two subtypes of Group I mGluRs in the regulation of behavioral sensitization to the dopamine stimulant.

Intrastriatal GABA(A) receptor blockade does not alter dopamine D(1)/D(2) receptor interactions in the intact rat striatum

The purpose of this study was to investigate the effects of intrastriatal blockade of GABA(A) receptors on dopamine D(1)/D(2) receptor interactions in the intact rat striatum. Muscarinic receptors mediate the ability of the D(2) receptor antagonist, eticlopride, to block an increase in striatonigral neuropeptide messenger RNA stimulated by the full D(1) agonist, SKF-82958. However, because D(2) receptor antagonists activate striatopallidal neurons, it is possible that increased GABA release from local medium spiny axon collaterals also contributes to the ability of eticlopride to block the effects of SKF-82958. This hypothesis was addressed by infusing the GABA(A) receptor antagonist, bicuculline, into the dorsal striatum in rats treated with eticlopride and SKF-82958. In contrast to the actions of the muscarinic antagonist, scopolamine, bicuculline did not affect the increase in behaviors induced by SKF-82958 or the ability of eticlopride to block them. Quantitative in situ hybridization demonstrated that bicuculline did not significantly affect basal preprodynorphin messenger RNA, nor did it affect the ability of eticlopride to decrease SKF-82958-induced preprodynorphin messenger RNA. However, the level of the preprodynorphin hybridization signal in bicuculline plus SKF-82958-treated rats was significantly lower than in saline plus SKF-82958-treated rats. In contrast, bicuculline, eticlopride or SKF-82958 by themselves increased basal preproenkephalin messenger RNA. However, there was no significant interaction among bicuculline, eticlopride and SKF-82958 on preproenkephalin messenger RNA levels.These data indicate that blockade of striatal GABA(A) receptors has only a subtle effect on acute dopamine agonist-induced changes in gene expression. These results are discussed in the context of local intrastriatal interactions.

[The study on non-contact detection of breathing and heartbeat based on radar principles]

The paper introduces the design of hardware and software of non-contact detection system for breathing and heartbeat in human body with radar principles and technology. The detection technology is discussed. Under conditions of the illuminating power P < 1 mW and the distance S < 10 m, the non-contact breathing and heartbeat measurement, can be in different positions and with different clothing on the subject. The results show that the system with the technology has a high sensitivity, and is harmless to the health. It is a practicable non-contact detection technology for breathing and heartbeat of human body.

Upregulation of preprodynorphin and preproenkephalin mRNA expression by selective activation of group I metabotropic glutamate receptors in characterized primary cultures of rat striatal neurons

Group I metabotropic glutamate receptors (mGluRs) are positively coupled to phosphoinositide hydrolysis, and are expressed in medium spiny neurons of rat striatum in vivo. By modifying intracellular activities, this group of mGluRs is involved in the regulation of gene expression important for neuroplasticity. To characterize the regulatory role of group I receptors in opioid peptide mRNA expression in vitro, primary cultures of striatal cells were prepared from neonatal day-1 rat pups. Cells were cultured in the presence of a mitotic inhibitor, cytosine arabinoside, which generated predominant neuronal cell cultures after 12-14 days in culture as demonstrated by dense immunostaining of more than 90% of cultured cells to a specific marker for neurons (microtubule-associated protein) but not for astroglial cells (glial fibrillary acidic protein). The vast majority of neurons (>90%) were also verified as GABAergic neurons according to their positive immunoreactivity to GABA and glutamic acid decarboxylase-65/67 antibodies. A few large neurons (<5%) showed high levels of choline acetyltransferase immunoreactivity, presumably cholinergic neurons. To confirm group I mGluR expression in cultured neurons, both in situ hybridization and immunocytochemistry were performed, which detected moderate levels of mGluR1 and mGluR5 mRNAs and protein products in most neurons (>70%), respectively. On this culture system, quantitative in situ hybridization was then performed to quantify changes in preprodynorphin (PPD) and preproenkephalin (PPE) mRNA levels in response to mGluR stimulation. Acute incubation of a non-subgroup selective agonist, 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD), increased PPD and PPE mRNA levels in a concentration-dependent manner (176 and 189% over control for PPD and PPE after 100 microM ACPD incubation, respectively). Application of a selective group I agonist, 3,5-dihydroxyphenylglycine (DHPG), produced much greater induction of either mRNA (285 and 289% over control for PPD and PPE after 100 microM DHPG incubation, respectively). Co-incubation of a selective group I antagonist, n-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC), blocked both ACPD- and DHPG-induced PPD/PPE expression. These data demonstrate the validity of a neuronal cell culture model for studying the molecular regulation of opioid gene expression in vitro. Selective activation of identified group I mGluRs facilitates constitutive expression of PPD and PPE mRNAs in cultured striatal neurons.

Selective activation of group I metabotropic glutamate receptors upregulates preprodynorphin, substance P, and preproenkephalin mRNA expression in rat dorsal striatum

Group I metabotropic glutamate receptors (mGluRs) are positively coupled to phosphoinositide hydrolysis through G-proteins and are densely expressed in the medium-sized spiny neurons of striatum. Activation of this group of mGluRs in the striatum produces long-lasting stimulation of behavioral activity. In this study, the role of group I mGluRs in the modulation of neuropeptide mRNA expression in striatal neurons was investigated using a Group I-selective agonist, 3,5-dihydroxyphenylglycine (DHPG) in chronically cannulated rats. Unilateral injections of DHPG into the dorsal striatum (caudoputamen) at behaviorally active doses of 20, 40, and 80 nmol elevated basal levels of preprodynorphin (PPD), substance P (SP), and preproenkephalin (PPE) mRNAs in the injected dorsal striatum as revealed by quantitative in situ hybridization. The elevation of all three mRNAs was dose-dependent and the responsiveness of opioid peptide mRNAs (PPD and PPE) to acute injection of DHPG at each dose surveyed was greater than that of SP mRNA. Induction of the mRNAs was delayed and prolonged as increases in hybridization signal became evident at 2 (SP and PPE) or 3 (PPD) h, reached a peak between 3 and 6 h, and returned to normal levels 24 h after DHPG injection. Coadministration of a Group I-selective antagonist, n-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carbo xamide (PHCCC, 10 nmol), with DHPG markedly attenuated DHPG-stimulated PPD, PPE, and, to a lesser extent, SP expression. Administration of PHCCC alone had no significant effect on basal levels of three mRNA expression in the striatum. This study provides a detailed description of the dose- and time-related alterations in striatonigral PPD/SP and striatopallidal PPE mRNA expression in response to a single injection of the Group I agonist DHPG. Data obtained demonstrate a facilitatory, dynamic regulation of constitutive expression of PPD, SP, and PPE mRNAs by local enhancement of glutamatergic tone on DHPG- and PHCCC-sensitive Group I mGluRs.

Activation of group III metabotropic glutamate receptors inhibits basal and amphetamine-stimulated dopamine release in rat dorsal striatum: an in vivo microdialysis study

Group III metabotropic glutamate (mGlu) receptors are negatively coupled to adenylate cyclase and are distributed pre-synaptically in the striatum. A behavioral study previously conducted in this laboratory shows that activation of this group of mGlu receptors attenuates acute amphetamine-stimulated motor activity. By administering a group III selective agonist or antagonist via the dialysis probe, the present study employed in vivo microdialysis to evaluate the capacity of the group III selective agents to alter extracellular levels of dopamine in the dorsal striatum of normal and amphetamine-treated rats. It was found that the group III agonist L-2-amino-4-phosphonobutyrate (L-AP4) dose-dependently (1, 10 and 100 microM) reduced basal levels of extracellular dopamine. In contrast, the group III antagonist alpha-methyl-4-phosphonophenylglycine (MPPG) dose-dependently (10, 50 and 250 microM) elevated the basal release of extracellular dopamine. This elevation was antagonized by co-perfusion of L-AP4. Perfusion of 5-microM amphetamine through the dialysis probe increased extracellular dopamine in the dorsal striatum. Co-perfusion of L-AP4 (100 microM) significantly reduced amphetamine-stimulated dopamine levels, whereas co-perfusion of L-AP4 (100 microM) and MPPG (100 microM) did not alter the capacity of amphetamine to elicit dopamine release. The data obtained from this study demonstrate the presence of a tonically active glutamatergic tone on group III mGlu receptors in the dorsal striatum to pre-synaptically regulate basal dopamine release in an inhibitory fashion. Moreover, activation of L-AP4-sensitive group III mGlu receptors can suppress the phasic release of dopamine induced by a dopamine stimulant amphetamine.

Distinct inhibition of acute cocaine-stimulated motor activity following microinjection of a group III metabotropic glutamate receptor agonist into the dorsal striatum of rats

Group III metabotropic glutamate receptors (mGluRs) are negatively coupled to adenylate cyclase through G-proteins. Activation of this group of mGluRs shows an inhibition of dopaminergic transmission in the forebrain. To define the role of striatal group III mGluRs in the regulation of basal and dopamine-stimulated motor behavior, the recently developed agonist and antagonist relatively selective for group III mGluRs were utilized to pharmacologically enhance and reduce group III mGluR glutamatergic tone in the dorsal striatum of chronically cannulated rats. Bilateral injections of a group III agonist, L-2-amino-4-phosphonobutyrate (L-AP4), did not alter basal levels of motor activity at three doses surveyed (1, 10, and 100 nmol). Neither did intracaudate injection of a group III antagonist, alpha-methyl-4-phosphonophenylglycine (MPPG), at 10, 30, and 100 nmol. However, pretreatment with L-AP4 (10 and 100 nmol) dose dependently blocked hyperlocomotion induced by acute injection of cocaine (20 mg/kg, i.p.), amphetamine (2.5 mg/kg, i.p.), or apomorphine (1 mg/kg, s.c.). The behavioral activity induced by cocaine was much more sensitive to L-AP4 than that induced by amphetamine and apomorphine. At 100 nmol, L-AP4 completely blocked cocaine effect whereas amphetamine- and apomorphine-stimulated behaviors were blocked only by 28% and 31%, respectively. The blocking effect of L-AP4 on cocaine action was reversed by pretreatment with MPPG. MPPG itself did not modify behavioral responses to cocaine, amphetamine, or apomorphine. These data indicate that the glutamatergic tone on the group III mGluRs is not active in the regulation of basal and acute dopamine-stimulated motor activity. However, enhanced group III mGluR glutamatergic transmission by an exogenous ligand is capable of suppressing behavioral responses to acute exposure of dopamine stimulants.

Microinjection of nociceptin (Orphanin FQ) into nucleus tractus solitarii elevates blood pressure and heart rate in both anesthetized and conscious rats

The role of nociceptinergic transmission in the nucleus tractus solitarii (NTS) in the central modulation of cardiovascular activity was investigated in pentobarbital-anesthetized and conscious rats. Pharmacological activation of nociceptin receptors with a unilateral injection of synthetic nociceptin into the NTS, wherein injection of L-glutamate (1 nmol) caused typical depressor responses, elevated blood pressure and heart rate (HR) in most of the anesthetized rats. The elevation of blood pressure and HR by nociceptin was dose-dependent (0.04, 0.2, and 1 nmol) with a threshold dose of 0.2 nmol. At 1 nmol, changes in blood pressure and HR were evident at 5 min, and remained for 45 min after injection. Pretreatment with the selective nociceptin receptor antagonist nocistatin (1 nmol) into the NTS abolished the nociceptin-induced hypertension and tachycardia. In contrast, the nonselective opioid receptor antagonist naloxone (5 nmol) did not modify the cardiovascular responses to nociceptin. Intra-NTS injection of nocistatin (0.04 and 1 nmol) and naloxone alone had no significant effect on baseline blood pressure and HR. In chronically cannulated and conscious rats, similar pressor and tachycardic responses were induced by intra-NTS injection of 1 nmol of nociceptin. However, changes in blood pressure and HR were rapid, and quickly returned to normal levels within 10 min. These data suggest that the newly discovered nociceptinergic transmission in the NTS has a powerful influence on peripheral hemodynamic activity. This influence is inhibitory and may not be tonically active under normal physiological conditions. Moreover, the cardiovascular responses to exogenous nociceptin were mediated through activation of specific nociceptin receptors rather than typical naloxone-sensitive opioid receptors.

Influence of some operational variables on the radial keratotomy operation

AIMS

To assess the contribution of the four major operational variables in the radial keratotomy operation (RK) to the correction of myopic eyes. To study the deformation of the cornea after the operation and provide some valuable references for clinical practice.

METHODS

The expression of the correction ratio has been deduced, which can be directly represent as the deformation ratio of the corneal radius after the operation. This allows for the numerical simulation of the RK operation. On the basis of the known biomechanical property of the cornea, by means of the finite element method, a series of computerised geometric and biomechanical models for the simulation of refractive surgery have been established. Some operational variables in the RK operation were analysed, and their influence on the operational outcome has been computed and systematically analysed.

RESULTS AND CONCLUSION

All of the four variables have a positive effect on the operational outcome. The greater the four variables are the more correction effects of myopia can be obtained. Because the four variables are interinfluential, the operational variables can be optimised to get the best result in order to meet patients' differing requirements.

[Extramedullary plasmacytoma of the head and neck: a clinicopathologic, immunohistochemistry study]

OBJECTIVE

To investigate the relation between histopathological feature, clinical behavior characters, immunoglobulin (Ig) secretory function and prognosis of the extramedullary plasmacytoma (EMP) of the head and neck.

METHOD

12 cases of EMP in the head and neck region were studied retrospectively. The clinicopathological records from January, 1977 to December, 1996 were reviewed. Immunohistochemical (IHC) stains for detecting intracytoplasmic immunoglobulin kappa (IgG kappa) and lambda (IgG lambda) were carried out.

RESULT

10 cases of the patients were male and 2 female; Their ages ranged from 32 to 67 years with an average of 57 years. The tumors were located in the nasosinus (6), nasopharynx (2), Larynx (3) and ear (1). Low-(I), intermediate (II) and high-grade (III) tumors were 3, 3 and 6 cases respectively. Two patients with EMP of nasopharynx were treated with radiotherapy, in others radiotherapy was administered after complete surgical resection. Follow-up time ranged from 10 to 76 months. IHC showed monoclonality of the plasma cell and was positive for IgG lambda (6 cases) and IgG kappa (6 cases, conferming the identical clonal origin of the plasma cells. The 5-year survival for grade I, II and III were 75.0%, 62.0% and 37.6%, 37.5% and 68.50% for IgG lambda positive and IgG kappa positive cases, respectively. There are statistically significance between them (P < 0.01).

CONCLUSION

EMP in head and neck region are rare plasma cell tumors. IHC play an important role in differential diagnosis. The combination of surgery and radiotherapy proved to be an adequate and effective treatment. The grading and IgG secretory function may be valuable for predicting the prognosis of EMP.

Sustained behavioral stimulation following selective activation of group I metabotropic glutamate receptors in rat striatum

Group I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium-sized spiny projection neurons of striatum. Activation of this group of the mGluRs modifies neuronal physiology through stimulation of phosphoinositide hydrolysis and intracellular Ca(2)+ release. Unlike the ionotropic glutamate receptors that mediate rapid synaptic transmission, activation of the mGluRs produces long-lasting actions brought about by modulation of activities of intracellular effectors. In this study, the role of the group I mGluRs in the modulation of extrapyramidal motor function was examined using a group I selective agonist, 3, 5-dihydroxyphenylglycine (DHPG), in chronically cannulated rats. Bilateral injections of DHPG at a series of subtoxic doses (20, 40, 80, and 160 nmol) into the central part of the dorsal striatum produced hyperlocomotion and a unique stereotypical behavior (spontaneous and repetitive twitching movement of the head and forepaws) in a dose-dependent manner. The characteristic twitchy behavior usually commenced 30 min to 1 h, and could last as long as 10 to 12 h, after a single injection of the group I agonist. The behavioral responses to DHPG administration were markedly antagonized by intrastriatal injection of the group I antagonist PHCCC (10 nmol), but not the group II/III antagonist MSOPPE (10 nmol). Intrastriatal administration of 20 nmol dantrolene, an inhibitor of intracellular Ca(2)+ mobilization, also prevented DHPG-stimulated motor activities. However, blockade of dopamine D(1) receptors with systemic administration of SCH-23390 (0.1 mg/kg, SC) did not alter the ability of DHPG to provoke behavioral activities. These data indicate that selective activation of the DHPG-sensitive group I mGluRs in the striatum can produce long-lasting stimulation of motor activity. DHPG-induced motor stimulation involves the mobilization of intracellular Ca(2)+ stores, but appears to be independent of D(1) dopaminergic transmission.

Motor stimulation following bilateral injection of the group-I metabotropic glutamate receptor agonist into the dorsal striatum of rats: evidence against dependence on ionotropic glutamate receptors

RATIONALE

Group-I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium-sized spiny projection neurons of the striatum. Activation of the group-I mGluRs in the rat striatum with a selective group-I agonist, 3,5-dihydroxyphenylglycine (DHPG), produced locomotion and stereotypical behavior.

OBJECTIVES

This study was designed to evaluate dependence of DHPG-stimulated motor behaviors on the ionotropic glutamate receptors [N-methyl-D-aspartate (NMDA) and kainate/alpha-amino-3-hydroxy-5-methyl-4-isoxazoleprionic acid (AMPA)].

METHODS

In chronically cannulated rats, effects on motor activity of DHPG injected into the dorsal striatum were examined in the presence or absence of the antagonists selective for NMDA or kainate/AMPA receptors.

RESULTS

Bilateral injections of DHPG (80 nmol) into the dorsal striatum induced a delayed locomotion followed by a prolonged stereotypical behavior characterized by the repetitive twitching movement of the head and forepaws. Blockade of NMDA receptors with intrastriatal injection of the NMDA receptor antagonist, (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP, 2.5 nmol), did not attenuate the behavioral changes induced by DHPG administration. Conversely, CPP unmasked an early onset of locomotion in response to DHPG injection as opposed to the delayed locomotion induced by DHPG in the absence of CPP. Pretreatment of rats with the kainate/AMPA receptor antagonist, 6,7-dinitroquinoxaline2,3-dione (DNQX, 10 nmol), had no effect on DHPG-stimulated behaviors. CPP administered alone sedated animals, whereas DNQX given alone did not alter spontaneous behavioral activity.

CONCLUSIONS

Motor stimulation induced by activation of the DHPG-sensitive group-I mGluRs in the striatum is independent upon co-activation of NMDA or kainate/AMPA receptors, since the NMDA or the kainate/AMPA receptor antagonist had no effect on DHPG-stimulated motor activity.

Pharmacological activation of nociceptin receptors in the nucleus tractus solitarius inhibits baroreceptor reflex in pentobarbital-anesthetized rats

Nociceptin receptors are densely distributed in the nucleus tractus solitarius pre- and postsynaptically. This study tested whether nociceptin receptors in this brain area are involved in the modulation of baroreceptor reflex. In pentobarbital-anesthetized rats, pharmacological activation of nociceptin receptors with bilateral microinjection of a synthetic peptide agonist, nociceptin, into the nucleus tractus solitarius attenuated baroreflex sensitivity as demonstrated by a marked reduction in baroreflex bradycardia induced by a single dose of intravenous phenylephrine. The inhibitory effect of nociceptin was dose dependent (0.04, 0.2 and 1nmol) and was blocked by pretreatment with microinjection of 1nmol nocistatin, a peptide that can functionally reverse the action of nociceptin. In contrast, injection of an opioid receptor antagonist, naloxone (5nmol), did not modify the inhibition of baroreflex sensitivity induced by nociceptin. Neither nocistatin nor naloxone injected into the nucleus alone had any detectable effect on baseline blood pressure and heart rate and baroreflex bradycardia. These data indicate that the newly discovered nociceptin receptors in the central nervous system possess an inhibitory influence on baroreflex transmission at the level of the nucleus tractus solitarius.

The role of dorsal striatal GABA(A) receptors in dopamine agonist-induced behavior and neuropeptide gene expression

The purpose of this study was to investigate whether GABA(A) receptors in the dorsal striatum regulate basal or stimulant-induced behaviors. Correspondingly, the question of possible GABA(A) receptor control of neuropeptide mRNA expression in nigrostriatal neurons was addressed. The GABA(A) receptor antagonist, bicuculline, was unilaterally or bilaterally microinjected into the dorsal striatum of rats in a series of 3 studies. In the first study, unilateral administration of 10-50 ng/microliter of bicuculline did not alter behavior. However, 250 ng/microliter bicuculline produced motor dyskinesias and/or seizures. In the second study, 100 ng/microliter bicuculline administered unilaterally prior to saline or amphetamine treatment, produced mild twitching in 61% of rats but did not affect amphetamine (2.5 mg/kg, i.p.)-induced behavioral activity, specifically rearing and sniffing. In the third study, 75 ng/microliter of bicuculline was administered unilaterally or bilaterally into the striatum in two separate experiments. Administration of bicuculline either unilaterally or bilaterally produced mild transient twitching of the forelimbs but did not affect behaviors induced by the selective D(1) receptor agonist SKF-82958 (0.5 mg/kg, s.c.). Three hours after unilateral bicuculline administration, the brains were removed and processed for quantitative in situ hybridization. Bicuculline did not significantly affect the basal or SKF-82958-induced increase in preprodynorphin or substance P mRNA expression in striatonigral neurons on the side of injection. These data suggest that blockade of GABA(A) receptors in the dorsal striatum does not affect dopamine agonist-stimulated behaviors or neuropeptide mRNA expression in striatonigral neurons in the rat striatum.

Protection against acute amphetamine-induced behavior by microinjection of a group II metabotropic glutamate receptor agonist into the dorsal striatum of rats

Group II metabotropic glutamate receptors (mGluRs) are distributed both pre- and postsynaptically in the striatum. By bilaterally administering a subgroup-selective agonist or antagonist into the dorsal striatum of chronically cannulated rats, this study examined the role of striatal group II mGluRs in the regulation of basal and dopamine-stimulated motor behavior. Intrastriatal injection of a group II agonist, (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV, 0.01, 0.1 and 1 nmol), dose-dependently reduced basal levels of motor activity. Pretreatment of rats with intrastriatal DCG-IV at a higher dose (1 nmol), but not a lower dose (0.01 nmol), produced complete or partial blockade of hyperlocomotion induced by acute injection of amphetamine (2.5 mg/kg, i.p.) or apomorphine (1 mg/kg, s.c.), respectively. Blockade of group II mGluRs by intrastriatal injection of a group II antagonist, (RS)-alpha-methylserine-O-phosphate monophenyl ester (10 nmol), was found to: (i) induce a moderate locomotion by itself; (ii) augment amphetamine-stimulated behaviors and (iii) attenuate DCG-IV-induced reduction of basal and amphetamine-stimulated motor activity. These data demonstrate that the group II mGluRs in the striatum play a significant role in the inhibitory modulation of tonic and phasic motor activity, which is most likely processed through both pre- and postsynaptic mechanisms.

Pharmacological regulation of striatal gene expression by metabotropic glutamate receptors

Metabotropic glutamate receptors (mGluR) are densely expressed by striatal medium spiny neurons. Activation of mGluR in this brain region alters local transmitter release and behaviors of experimental animals. In particular, mGluR regulate transcription factor and neuropeptide gene expression in striatal neurons through their connections with multiple intracellular effectors. This prominent involvement of mGluR in overall cellular activity is pivotal for the development of neuronal plasticity underlying long-term adaptive changes in cellular physiology related to a variety of neurologic disorders. Accumulating evidence demonstrates that the subtypes of mGluR have distinct effects on gene expression: group I subtypes facilitating, and group II/III subtypes inhibiting, gene expression. Thus, the mGluR can be considered as promising targets in the development of novel therapeutic drugs that can relieve neurologic disorders resulting from dysfunction of the striatum.

Inhibition of cardiovascular activity following microinjection of novel opioid-like neuropeptide nociceptin (orphanin FQ) into the rat rostral ventrolateral medulla

Nociceptin (orphanin FQ), the newly discovered endogenous ligand for the novel opioid receptor-like 1 receptor, has been initially found to participate in pain modulation. In this study, centrally mediated cardiovascular actions of this peptide were investigated in the alpha-chloralose/urethane-anesthetized rats. We found that bilateral injection of nociceptin (10 nmol) into the rostral ventrolateral medulla (RVLM), wherein injection of excitatory amino acid dl-homocysteic acid (3 nmol) induced typical pressor responses, significantly reduced arterial blood pressure and heart rate by -32% and -15%, respectively. Reduction of blood pressure and heart rate in response to intra-RVLM injection of nociceptin was dose-dependent with a threshold dose being 3 nmol. Pretreatment with the selective nociceptin receptor antagonist, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 (10 nmol), into the RVLM abolished the nociceptin-induced cardiovascular inhibition. In contrast, non-selective opioid receptor antagonist, naloxone (10 nmol), did not modify the hypotension and bradycardia induced by nociceptin, even though naloxone at the same dose prevented reduction of blood pressure and heart rate induced by intra-RVLM injection of methionine-enkephalin (3 nmol). Both [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 and naloxone injection alone had no significant effect on baseline blood pressure and heart rate. These data suggest that the newly discovered opioid-like neuropeptide nociceptin in the CNS exert powerful influence on hemodynamic activity by affecting the RVLM neurons. This influence is inhibitory in nature, which may not be active in normal physiological conditions. Moreover, the cardiovascular effects of nociceptin were mediated by activation of specific nociceptin receptors rather than typical naloxone-sensitive opioid receptors.

Endomorphin-1 and endomorphin-2, endogenous ligands for the mu-opioid receptor, inhibit electrical activity of rat rostral ventrolateral medulla neurons in vitro

The classic opioid peptide, enkephalin, and the novel member of the opioid family, nociceptin/orphanin FQ, inhibit the spontaneous electrical activity of neurons recorded from the rostral ventrolateral medulla, presumably cardiovascular neurons. In this study, the putative effects of endomorphin-1 and endomorphin-2, the newly discovered endogenous ligands for the micro-opioid receptor, on the electrical activity of rostral ventrolateral medulla neurons were investigated in rat brain slices in vitro. Like enkephalin and nociceptin, perfusion of endomorphin-1 or endomorphin-2 profoundly inhibited spontaneous discharges of 43% and 38% of the medullary neurons, respectively. No excitatory response to perfusion of either endomorphin was found in all neurons surveyed. Both endomorphins produced concentration-dependent inhibition. However, endomorphin-1 was more potent than endomorphin-2 for production of the inhibition, as demonstrated by the greater and longer suppression induced by endomorphin-1 than that induced by endomorphin-2 at the same concentration. Among the four opioid agonists tested, EC50 values (in nM) were 3.17 (endomorphin-1), 3.02 (nociceptin), 10.1 (endomorphin-2) and 150.0 (enkephalin). The non-selective opioid receptor antagonist, naloxone, blocked the inhibitory responses of the neurons to endomorphin-1, endomorphin-2 and enkephalin, but not to nociceptin. The selective mu antagonist, beta-funaltrexamine, prevented the neuronal inhibition induced by endomorphins, but not by enkephalin and nociceptin. Neither naloxone nor beta-funaltrexamine alone had a significant effect on the firing rate of the neurons. These results demonstrate that endomorphin-1 and, to a lesser extent, endomorphin-2 exert an inhibitory modulation of the electrical activity of rostral ventrolateral medulla neurons, which is mediated through the stimulation of mu-opioid receptors.

The nociceptin receptor-mediated inhibition of the rat rostral ventrolateral medulla neurons in vitro

The recently available antagonist selective for novel nociceptin receptor, [Phe1 psi(CH2-NH)Gly2]NC(1-13)NH2, was utilized in this study to verify specificity of nociceptin receptor in mediating the nociceptin-induced inhibition of electrical activity of neurons in the rostral ventrolateral medulla of rat brain slices. Perfusion of nociceptin (10 nM) considerably reduced spontaneously firing frequency of the medullary neurons. Co-perfusion of [Phe1 psi(CH2-NH)Gly2]NC(1-13)NH2 (10 microM) completely blocked the nociceptin-induced depression of the neuronal activity. Blocking effect of [Phe1 psi(CH2-NH)Gly2]NC(1-13)NH2 was concentration-dependent. However, the nociceptin antagonist did not modify basal, and opioid peptide enkephalin-depressed, firing rates of the neurons. In contrast to [Phe1 psi(CH2-NH)Gly2]NC(1-13)NH2, the non-selective opioid receptor antagonist naloxone (10 microM) failed to affect the nociceptin inhibition even though naloxone at a lower concentration (1 microM) readily blocked enkephalin-induced depression of the neuronal activity. These data indicate that the nociceptin-induced inhibition of spontaneous discharge of the rostral ventrolateral medulla neurons is specifically mediated by [Phe1 psi(CH2-NH)Gly2]NC(1-13)NH2-sensitive nociceptin receptors distinct from typical naloxone-sensitive opioid receptors.

Regulation of immediate early gene c-fos and zif/268 mRNA expression in rat striatum by metabotropic glutamate receptor

Metabotropic glutamate receptors are coupled to multiple intracellular second messenger systems through G-proteins and densely expressed by medium spiny projection neurons in the rat striatum. In chronically-cannulated rats, this study demonstrated that pharmacological activation of metabotropic glutamate receptors by intrastriatal injection of a selective agonist, ACPD, elevated immediate early gene c-fos and zif/268 mRNA expression in the injected dorsal striatum as revealed by quantitative in situ hybridization. The elevation of both c-fos and zif/268 was dose-dependent and the responsiveness of c-fos to ACPD at each dose surveyed was greater than that of zif/268. Induction of the two mRNAs was rapid and transient as increases in the 2 mRNAs became evident as early as 30 min, reached a peak at 1 h, and returned to normal levels 3 (c-fos) or 6 (zif/268) h, after ACPD injection. Coadministration of the selective metabotropic glutamate receptor antagonist, MCPG, with ACPD markedly attenuated ACPD-stimulated c-fos, but not zif/268, expression. Pretreatment with the ionotropic NMDA receptor antagonist, CPP, had no effect on ACPD-stimulated c-fos expression, but partially attenuated ACPD-stimulated zif/268 expression. Blockade of D1 dopamine receptors with SCH-23390 did not alter the ability of ACPD to induce the expression of these genes. These data demonstrate a difference between the profound induction of c-fos and zif/268 gene expression in response to specific activation of metabotropic glutamate receptors in striatal neurons. Furthermore, c-fos induction was independent of D1 dopaminergic and NMDA glutamatergic transmission, whereas zif/268 induction was mediated, at least in part, by NMDA receptors.

Profound inhibition of cardiomotor neurons in the rat rostral ventrolateral medulla by nociceptin (orphanin FQ)

Nociceptin (orphanin FQ), the newly discovered endogenous ligand for the opioid receptor like-1 receptor, profoundly inhibited spontaneous discharges of neurons in the rostral ventrolateral medulla (RVLM) in rat brain slices. This inhibition was concentration-dependent (0.3, 1, 3 and 10 nM) and insensitive to pharmacological blockade of traditional opioid receptors by naloxone. Moreover, nociceptin injected into the RVLM (10 nM, 0.1 microliter) in anesthetized rats decreased arterial blood pressure and heart rate by 31% and 15%, respectively. The data obtained in vitro and in vivo suggest that nociceptin has powerful effects on the RVLM neurons involving central control of cardiovascular activity. The negative regulation of cardiovascular activity by nociceptin is not mediated through typical naloxone-sensitive opioid receptors.

Metabotropic glutamate receptor agonist increases neuropeptide mRNA expression in rat striatum

Metabotropic glutamate receptors (mGluR) are coupled to multiple intracellular second messenger systems through G-proteins and densely expressed by medium spiny projection neurons in the rat striatum. Unlike ionotropic glutamate receptors which mediate rapid synaptic transmission, mGluRs are important for relatively long-lasting modulation of neuronal metabotropic activity, possibly including gene expression, in response to cellular stimulation. In this study, the effects of acute injection of the selective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD) on behavior and striatal neuropeptide mRNA expression were evaluated in chronically-cannulated rats. Unilateral injection of ACPD into the dorsal striatum at doses of 0.8, 4, 20, 100, 500 and 1000 nmol had no significant effect on spontaneous behavioral activity. However, intrastriatal ACPD (0.8, 4, 20 and 100 nmol) dose-dependently elevated preprodynorphin (PPD), substance P (SP) and preproenkephalin (PPE) mRNA expression in the dorsal striatum as revealed by quantitative in situ hybridization. PPD/SP mRNAs showed a biphasic response to a single injection of ACPD as the expression of these two mRNAs was increased at 3 and 6 h, decreased at 11 h, and returned to normal 24 h after ACPD administration. PPE induction in the dorsal striatum was significantly elevated as early as 2 h and remained even 24 h after ACPD was injected. In addition, the PPD and PPE mRNA induction by ACPD was blocked by intrastriatal pretreatment with the selective mGluR antagonist, (+)-alpha-methyl-4-carboxyphenyl-glycine. These data demonstrate a facilitatory regulation of constitutive expression of striatonigral PPD/SP, and striatopallidal PPE, mRNAs by local mGluR-mediated glutamatergic transmission.

The muscarinic toxin 3 augments neuropeptide mRNA in rat striatum in vivo

The selective M4 muscarinic receptor toxin, MT3, was used in vivo to evaluate the role of M4 receptors in cholinergic inhibition of neuropeptide mRNA expression in striatonigral neurons. Unilateral injection of the muscarinic toxin 3 (0.04-4 nmol) into the dorsal striatum of chronically-cannulated rats elevated basal levels of preprodynorphin, substance P and preproenkephalin mRNAs in the ipsilateral dorsal striatum as revealed by quantitative in situ hybridization. Pretreatment with muscarinic toxin 3 also augmented amphetamine (2.5 mg/kg, i.p.)-stimulated preprodynorphin and substance P expression in the dorsal striatum in a manner similar to that observed after the muscarinic antagonist, scopolamine. Since muscarinic toxin 3 has a much greater affinity for muscarinic M4 receptors than for other subtypes, it is possible that muscarinic toxin 3, by interacting with the muscarinic M4 subtype, regulates basal and/or dopamine-stimulated striatal neuropeptide gene expression.

The full D1 dopamine receptor agonist SKF-82958 induces neuropeptide mRNA in the normosensitive striatum of rats: regulation of D1/D2 interactions by muscarinic receptors

Neuropeptide and immediate early gene expression in striatonigral neurons of the normosensitive striatum is induced by mixed D1/D2 receptor agonists and indirect dopamine agonists, such as cocaine and amphetamine. Both D1 and D2 receptor antagonists block these events. In contrast, the partial D1 agonist, SKF-38393, does not evoke striatonigral gene expression in intact rats. These findings have contributed to the idea that both D1 and D2 receptors must be stimulated to evoke gene expression in striatonigral neurons. How these "D1/D2 interactions" are accomplished is unclear in light of the controversy over whether striatonigral neurons express both D1 and D2 receptors. This study addresses these issues by demonstrating that in intact rats 1) a full D1 receptor agonist, SKF-82958, induced behavioral activity and preprodynorphin (PPD) and substance P (SP) gene expression in medium spiny neurons in the dorsal, and especially, in the ventral striatum, 2) either a D1 antagonist, SCH-23390, or a D2 antagonist, eticlopride, blocked these effects, 3) the muscarinic antagonist, scopolamine, augmented PPD and SP mRNA expression induced by SKF-82958 and prevented the ability of eticlopride to block SKF-82958-induced PPD and SP mRNAs and 4) the SKF-82958-induced increase in preproenkephalin mRNA in striatopallidal neurons was blocked by SCH-23390 or scopolamine but not by eticlopride. These data indicate that endogenous acetylcholine attenuates D1 receptor-stimulated PPD/SP gene expression in medium spiny neurons, mediates D1 receptor-stimulated preproenkephalin gene expression in striatopallidal neurons and contributes to D2 receptor involvement in D1-stimulated PPD/SP gene expression.

Intrastriatal injection of a muscarinic receptor agonist and antagonist regulates striatal neuropeptide mRNA expression in normal and amphetamine-treated rats

Systemic administration of the muscarinic receptor antagonist, scopolamine, augments, whereas the muscarinic receptor agonist, oxotremorine, attenuates behaviors (locomotion and stereotypies) and preprodynorphin (PPD) and substance P (SP) gene expression in striatonigral neurons induced by the indirect dopamine receptor agonist, amphetamine (AMPH). In contrast, systemic scopolamine blocks, whereas oxotremorine augments, AMPH-stimulated preproenkephalin (PPE) gene expression in striatopallidal neurons. This study investigated the site of action of these effects by administering scopolamine and oxotremorine directly into the striatum and assessing the expression of neuropeptide mRNAs with quantitative in situ hybridization. Unilateral injection of scopolamine into the dorsal striatum augmented, and oxotremorine attenuated, AMPH (2.5 mg/kg, i.p.)-stimulated behaviors. Intrastriatal scopolamine at a concentration of 62 mM, but not 6.2 mM, increased basal levels of PPD and SP mRNAs in the dorsal striatum. In addition, both 6.2 and 62 mM scopolamine significantly augmented AMPH-stimulated PPD and SP mRNA levels. Intrastriatal infusion of 1.6 or 8.1 mM oxotremorine did not alter basal levels of striatal PPD and SP mRNAs. However, both concentrations of oxotremorine completely blocked AMPH-stimulated SP mRNA and oxotremorine at 8.1 mM blocked AMPH-stimulated PPD mRNA. In contrast, PPE induction by AMPH was blocked by 62, but not 6.2, mM scopolamine. Both concentrations of oxotremorine tended to augment basal and AMPH-stimulated PPE mRNA in the dorsal striatum but the trend was not significant. These data demonstrate an inhibition of striatonigral, and facilitation of striatopallidal, gene expression through activation of local striatal muscarinic receptors, which is consistent with the changes seen after systemic administration of muscarinic agents. Therefore, muscarinic cholinergic regulation of basal and stimulated expression of neuropeptide mRNA is processed within the striatum.