Simultaneous red/green dual fluorescence detection on electroblots using BODIPY TR-X succinimidyl ester and ELF 39 phosphate

A two-color fluorescence detection method is described based upon covalently coupling the succinimidyl ester of BODIPY TR-X dye to proteins immobilized on polyvinylidene difluoride membranes, followed by detection of target proteins using the fluorogenic, precipitating substrate ELF 39-phosphate in combination with alkaline phosphatase conjugated reporter molecules. This results in all proteins in the profile being visualized as fluorescent red signal while those detected specifically with the alkaline phosphatase conjugate appear as fluorescent green signal. The dichromatic detection system is broadly compatible with ultraviolet epi- or trans-illuminators combined with photographic or charge-coupled device cameras, and xenon-arc sources equipped with appropriate excitation/emission filters. The dichromatic method permits detection of low nanogram amounts of protein and allows for unambiguous identification of target proteins relative to the entire protein profile on a single electroblot, obviating the need to run replicate gels that would otherwise require visualization of total proteins by silver staining and subsequent alignment with chemiluminescent or colorimetric signals generated on electroblots. Combining the detection approach with an Alexa Fluor 350 dye conjugated monoclonal antibody permits simultaneous fluorescence detection of two antigens and the total protein profile on the same electroblot.

Urban stress and mental health among African-American youth: assessing the link between exposure to violence, problem behavior, and coping strategies

This project examines gender differences in exposure to violence, coping strategies and problem behavior among 306 African-American middle and high school students in the state of Virginia. Gender differences in problem behaviors among youth exposed to violence as either victims or witnesses are examined in addition to variations in coping strategies. Relying on recent research examining violent behavior and victimization events, the study focuses on the internalizing and externalizing behavioral characteristics (i.e., academic achievement, anxiety, depression, negative self-esteem, and delinquency) of urban students exposed to violence and the extent to which coping strategies differ. Results show specific gender differences with regard to problem behavior and coping strategy among African-American youth exposed to violence. For adolescent males, exposure to violence and victimization is strongly associated with externalizing problem behaviors such as delinquency, while adolescent females exposed to violence and victimization are more likely to exhibit internalizing symptoms indicative of post-traumatic stress disorder. Among students exposed to violence and victimization, females are more likely to use problem-focused coping (i.e., social support) as an adaptive strategy in comparison to males. Implications for intervention and future research are discussed.

Chronic substance P (NK1) receptor antagonist and conventional antidepressant treatment increases burst firing of monoamine neurones in the locus coeruleus

The mechanism of action of conventional antidepressants (e.g. imipramine) has been linked to modulation of central monoamine systems. Substance P (NK1) receptor antagonists may have antidepressant and anxiolytic effects in patients with major depressive disorder and high anxiety but, unlike conventional antidepressants, are independent of activity at monoamine reuptake sites, transporters, receptors, or monoamine oxidase. To investigate the possibility that substance P receptor antagonists influence central monoamine systems indirectly, we have compared the effects of chronic administration of imipramine with that of the substance P receptor antagonist L-760735 on the spontaneous firing activity of locus coeruleus neurones. Electrophysiological recordings were made from brain slices prepared from guinea-pigs that had been dosed orally every day for 4 weeks with either L-760735 (3 mg/kg), imipramine (10 mg/kg), or vehicle (water), or naive animals. Chronic, but not acute, treatment with the substance P receptor antagonist L-760735, induced burst firing of neurones in the locus coeruleus. This effect resembles that of the conventional antidepressant imipramine. However, their effects are dissociable since, in contrast to chronic imipramine treatment, chronic L-760735 treatment does not cause functional desensitisation of somatic alpha2 adrenoceptors. The mechanism by which chronic substance P receptor antagonist or conventional antidepressant treatment influences the pattern of firing activity of norepinephrine neurones remains to be elucidated. However, an indirect action in the periphery or distant brain nuclei has been excluded by the use of the in vitro slice preparation, suggesting a local site of action in the locus coeruleus.

Nest-Site Reuse Patterns for a Cavity-Nesting Bird Community in Interior British Columbia

Most obligate cavity-nesting birds are considered to be nest-site limited, either by time or energy to excavate or to acquire suitable holes for nesting. We examined rates of nest-cavity reuse for a rich community of cavity-nesting birds in mixed forests in interior British Columbia. Using a sample of 402 cavity-reuse cases over five years, we measured cavity reuse for 20 cavity-nesting bird and mammal species (three guilds), and examined the relationship between nest-cavity reuse and features of cavities, nest trees, and forest stands. Eight percent of used cavities were destroyed between years. Reuse rates were 17% for the cavities of weak excavators such as nuthatches and chickadees, 28% for formerly active woodpecker nests, and 48% for cavities previously used by secondary cavity nesting birds, but there was considerable species variation within all guilds. Nest cavities in aspen that were deep with large entrances had the highest reuse. At the forest stand level, cavities in trees close to edges and in sites with more edge habitat had greater reuse. Reused cavities tended to be occupied in sequential years rather than being inactive for a year. With increasing amounts of managed landscapes, availability of suitable cavities for forest nesting vertebrates is decreasing. Reuse of existing cavities might help mitigate the problem of nest-site limitation.

[Surveillance of permanent central venous access for hemodialysis]

Central venous catheters have emerged as a valuable alternative for permanent access in hemodialysis. Thanks to steady improvements of materials and design they have been successfully used as bridging solution until another vascular access became available or even long term solution for patients with limited or insuffisant vascular resources. Since the use of central venous catheters is affiliated with a higher dysfunction rate and morbidity, special attention is indicated. This should include regular surveillance, clinical examination and intervention using specific methods, bacteriological exams and regular dialysis quantification. Such a constant quality control followed by strict and adapted rules for catheter handling are essential necessities to reduce catheter-related complications and assure an adequate dialysis.

Patients' and carers' preferences in two models of care for acute exacerbations of COPD: results of a randomised controlled trial

BACKGROUND

Patients with an acute exacerbation of chronic obstructive pulmonary disease (COPD) were randomised to either hospital at home (HaH) or inpatient management, and patient and carer preferred site of management and satisfaction with care received in the two arms was determined.

METHODS

Emergency admissions with an acute exacerbation of COPD were randomised to inpatient care or HaH care. After discharge an independent observer administered a questionnaire to both patients and carers on the preferred site of care and scored satisfaction with the care received.

RESULTS

Of 60 patients recruited, 30 were randomised to receive HaH care. Retrospective patient preference for HaH care was 96.3% in the domiciliary arm and 59.3% in the conventional arm; carer preference figures were 85.7% and 42.9%, respectively. There was a higher preference for domiciliary care by both patients and carers in the HaH arm than in the inpatient arm (p=0.001 and p=0.01, respectively). Patients recorded equal satisfaction with care in the two arms (88.1% in the conventional arm, 91.7% in the domiciliary arm); carer scores were 91.3% and 91.9%, respectively.

CONCLUSIONS

The results of this study show that both patients and carers were significantly more likely to prefer domiciliary care if they were in the HaH arm. Since patients had to be willing to be looked after at home, both patients' and carers' perceptions of the benefits of HaH care were reinforced by their experience. HaH care of acute exacerbations of COPD is the preferred option in suitable patients.

Detection of diluted gene expression alterations using cDNA microarrays

The use of DNA microarrays has spanned numerous disciplines of life science research. Despite the volume of studies utilizing this technology, no consensus exists on basic issues such as the determination of significantly altered genes in a given experiment, often leading to either false-negative or false-positive data. In this report, we study the effect of dilution of biological alterations on the detection level of gene expression differences using cDNA microarrays. We propose that subtle alterations in transcript levels of genes below the 2-fold level should be considered when replicate hybridizations are performed, because these subtle gene expression changes may be due to a robust response in few cells. We measured the effect of dilution of gene expression and found that differences in gene expression between the two cell lines assayed (HaCaT and MCF-7) were detected even after a 20-fold dilution factor. These results better our understanding of biological alterations that comprise a relatively small percentage of an assayed organ and help in the interpretation of gene expression data.

Effects of acetaminophen on monoaminergic systems in the rat central nervous system

Although acetaminophen is a well established analgesic, its mechanism of action is still unknown. We investigated whether this drug could affect central monoaminergic neurotransmission in rats. Significant increases in serotonin (5-HT) levels were found in the posterior cortex, hypothalamus, striatum, hippocampus and brain stem, but not spinal cord, 45 min after per os administration of 200-400 mg/kg of acetaminophen. However, this treatment altered neither the levels of 5-hydroxyindoleacetic acid nor the accumulation of 5-hydroxytryptophan after blockade of aromatic L-amino acid decarboxylase. On the other hand, a decrease in both the levels of the dopamine (DA) metabolite, dihydroxyphenylacetic acid, and the accumulation of dihydroxyphenylalanine were noted in the striatum of acetaminophen-treated rats. Finally, acetaminophen administration significantly increased noradrenaline (NA) levels in the posterior cortex. In vitro studies showed that acetaminophen (1 mM) enhanced K+-evoked overflow of [3H]5-HT, but not [3H]DA and [3H]NA, previously taken up in brain slices, and exerted no direct effect on monoamine oxidase A, tyrosine hydroxylase and catechol-O-methyl-transferase activities. These results indicate that acetaminophen affects central monoaminergic neurotransmission, thereby suggesting that monoamines (especially 5-HT) might participate in its analgesic action.

Polymorphisms of the ICAM-1 gene are associated with inflammatory bowel disease, regardless of the p-ANCA status

The intercellular adhesion molecule-1 (ICAM-1) is of paramount importance for the initiation and propagation of various inflammatory conditions. An increased frequency of allele R241 of the ICAM-1 gene was previously described in p-ANCA-negative as compared to p-ANCA-positive ulcerative colitis and vice versa in Crohn's disease. One hundred sixteen healthy unrelated controls, 121 patients with ulcerative colitis, and 96 patients with Crohn's disease were genotyped for two polymorphisms of the ICAM-1 gene (R/G241, exon 4; and K/E469, exon 6), employing dot-blot hybridization and stratified according to their p-ANCA status. When compared with the control group the frequency of the allele R241 (P = 0.024) and the heterozygous genotype R/G241, P = 0.032) were significantly increased in ulcerative colitis, whereas the homozygous genotype G/G241 was found less frequently (P = 0.022). The heterozygous genotype K/E469 was observed less frequently (P = 0.001 and 0.037, resp.) than the homozygous genotype E/E469, which was more frequent in Crohn's disease and ulcerative colitis (P = 0.002 and 0.012, respectively). Further significant differences concerning the allele or genotype distribution were not observed. After stratification for the p-ANCA status significant differences concerning the frequencies of both the R241 and the E469 alleles were not detected when p-ANCA-positive inflammatory bowel disease and p-ANCA-negative inflammatory bowel disease were compared. Ulcerative colitis and Crohn's disease are associated with polymorphisms of the ICAM-1 gene, which might therefore represent a functional candidate gene. However, the observed associations are independent of the p-ANCA status.

Efficacy and tolerability of a fixed-dose combination of telmisartan plus hydrochlorothiazide in patients uncontrolled with telmisartan monotherapy

The antihypertensive effects of a telmisartan 80 mg/hydrochlorothiazide (HCTZ) 12.5 mg fixed-dose combination and telmisartan 80 mg monotherapy were compared in patients with a history of mild-to-moderate essential hypertension and inadequate BP control (DBP > or = 90 mm Hg) following 8 weeks of telmisartan monotherapy. At the end of this period, 491 patients (62.9% men; mean age 55.3 years) whose DBP was > or = 90 mm Hg were double-blind randomised to once-daily telmisartan 80 mg/HCTZ 12.5 mg (n = 246) or telmisartan 80 mg (n = 245). Trough (24 h post-dose) clinic BP was measured after 4 and 8 weeks of double-blind therapy. At the end of double-blind treatment, patients receiving telmisartan 80 mg/HCTZ 12.5 mg had significant additional decrements in clinic SBP/DBP over telmisartan 80 mg of -5.7/-3.1 mm Hg (P < 0.01). Most of the additional effect occurred during the first 4 weeks of treatment. The proportion of patients with normalised BP (SBP < 140 mm Hg and DBP < 90 mm Hg) was significantly greater in the telmisartan 80 mg/HCTZ 12.5 mg group than the telmisartan 80 mg group (41.5%vs 26.1%;P < 0.05). Both treatments were well tolerated. The incidence of adverse events was similar except for diarrhoea, which occurred more frequently in the telmisartan 80 mg/HCTZ 12.5 mg group, and oedema, which occurred more frequently in the telmisartan group. Our results indicate that a telmisartan 80 mg/HCTZ 12.5 mg fixed-dose combination confers significant additional BP reductions compared with continuation of telmisartan monotherapy in non-responders.

MICA, MICB and C1_4_1 polymorphism in Crohn's disease and ulcerative colitis

MICA and MICB belong to a multicopy gene family located in the major histocompatibility complex (MHC) class I region near the HLA-B gene. They encode for MHC class I molecules, which are induced by stress factors like infection, heat shock or neoplastic transformation and which are mainly expressed on gastrointestinal epithelium. They are recognized by gammadelta T lymphocytes and natural killer (NK) cells. Additionally they are located within a linkage region on chromosome 6p around HLA-B and TNFalpha. Thus the polymorphic MICA and MICB genes are excellent candidate genes for providing the genetic background of inflammatory bowel disease. A strong association of allele A6 of the MICA exon 5 trinucleotide microsatellite polymorphism with ulcerative colitis has been found in Japanese patients. Therefore, we have analysed the MICA exon 5 polymorphism, the MICB intron 1 dinucleotide polymorphism and in addition the tetranucleotide polymorphism C1_4_1, which is located between the MICA gene and the HLA-B gene, in patients of Caucasoid origin with Crohn's disease (n=94) and ulcerative colitis (n=94). In this study we could not find any associations of particular alleles of the MICA, MICB and C1_4_1 polymorphisms with Crohn's disease or ulcerative colitis. We could also not discover any associations of specific two-point or three-point haplotypes with these diseases. Thus it is unlikely that the MICA and MICB genes are involved in causing susceptibility for inflammatory bowel disease, although it cannot be excluded that a weak association could be identified in a larger patient sample.

[Cardiac neuroses]

Cardiac neurosis is defined as heart complaints for which no organic cause can be found. Other common terms are "cardiac anxiety neurosis", "cardiac anxiety disorder", "cardiac phobia", "functional heart complaints" and "somatoform autonomous functional disorders of the cardiovascular system" (ICD-10). Although cardiac neurosis is rarely diagnosed, it is estimated that approximately 30 bis 40% of patients with cardiovascular disorders are actually suffering from functional complaints. Predisposing to the development of cardiac neurosis are insufficient internalization processes during childhood, leading to an insoluble autonomy dependency conflict. Cardiac neurosis is treated with drugs and psychotherapy.

Carbon partitioning to cellulose synthesis

This article discusses the importance and implications of regulating carbon partitioning to cellulose synthesis, the characteristics of cells that serve as major sinks for cellulose deposition, and enzymes that participate in the conversion of supplied carbon to cellulose. Cotton fibers, which deposit almost pure cellulose into their secondary cell walls, are referred to as a primary model system. For sucrose synthase, we discuss its proposed role in channeling UDP-Glc to cellulose synthase during secondary wall deposition, its gene family, its manipulation in transgenic plants, and mechanisms that may regulate its association with sites of polysaccharide synthesis. For cellulose synthase, we discuss the organization of the gene family and how protein diversity could relate to control of carbon partitioning to cellulose synthesis. Other enzymes emphasized include UDP-Glc pyrophosphorylase and sucrose phosphate synthase. New data are included on phosphorylation of cotton fiber sucrose synthase, possible regulation by Ca2+ of sucrose synthase localization, electron microscopic immunolocalization of sucrose synthase in cotton fibers, and phylogenetic relationships between cellulose synthase proteins, including three new ones identified in differentiating tracheary elements of Zinnia elegans. We develop a model for metabolism related to cellulose synthesis that implicates the changing intracellular localization of sucrose synthase as a molecular switch between survival metabolism and growth and/or differentiation processes involving cellulose synthesis.

Carbon partitioning to cellulose synthesis

This article discusses the importance and implications of regulating carbon partitioning to cellulose synthesis, the characteristics of cells that serve as major sinks for cellulose deposition, and enzymes that participate in the conversion of supplied carbon to cellulose. Cotton fibers, which deposit almost pure cellulose into their secondary cell walls, are referred to as a primary model system. For sucrose synthase, we discuss its proposed role in channeling UDP-Glc to cellulose synthase during secondary wall deposition, its gene family, its manipulation in transgenic plants, and mechanisms that may regulate its association with sites of polysaccharide synthesis. For cellulose synthase, we discuss the organization of the gene family and how protein diversity could relate to control of carbon partitioning to cellulose synthesis. Other enzymes emphasized include UDP-Glc pyrophosphorylase and sucrose phosphate synthase. New data are included on phosphorylation of cotton fiber sucrose synthase, possible regulation by Ca2+ of sucrose synthase localization, electron microscopic immunolocalization of sucrose synthase in cotton fibers, and phylogenetic relationships between cellulose synthase proteins, including three new ones identified in differentiating tracheary elements of Zinnia elegans. We develop a model for metabolism related to cellulose synthesis that implicates the changing intracellular localization of sucrose synthase as a molecular switch between survival metabolism and growth and/or differentiation processes involving cellulose synthesis.

Weight Loss and Exercise Walking Reduce Pain and Improve Physical Functioning in Overweight Postmenopausal Women with Knee Osteoarthritis

We conducted an uncontrolled pilot study to determine the effects of a weight loss and walking program on knee pain and physical function in overweight and obese (body mass index; BMI [kg/m] 25-29.9 and BMI > or = 30, respectively) postmenopausal women with knee osteoarthritis (OA). Forty-eight such women completed self-report (Western Ontario and McMaster University Osteoarthritis Index (WOMAC)) and performance-based measures of physical function ("up and go" test, 6-min walk) and enrolled in a 6-month intervention that included weekly nutrition classes and an exercise-walking program. The intervention produced an average weight loss of 5.6 +/- 4.0 kg in the 30 women who completed the program. There also were significant improvements in the 6-min walk and on VO(2max). Improvements in the timed up and go test and on the WOMAC pain and function scores, however, were restricted only to women who were classified as obese at baseline. These findings suggest that a 6-month weight loss and walking program improves measures of physical functioning and pain in overweight and obese postmenopausal women with knee OA. Among obese women, functional improvement correlated with weight loss, encouraging continued emphasis on weight loss for managing knee OA.

Ageing of murine small intestinal stem cells

Most organs of the body comprise populations of cells that are committed to specialized functions and that are renewed from small numbers of uncommitted progenitor or 'stem' cells. Stem cells are of central importance in the study of ageing because any senescent decline in the number or functional competence of stem cells will impair the capacity for renewal and turnover of committed cells, with potentially serious consequences for tissue homeostasis. The intestinal epithelium represents an excellent model system for the study of stem cells. Its spatial and hierarchical organisation allows the study of the function or characteristic of a given cell according to its position within the crypt. Hence, the stem cells which are located at the 4th-5th cell position from the bottom can be studied together with their daughter cells, as they divide and differentiate while migrating along the crypt-villus axis. The ability of the stem cells to undergo apoptosis and the capacity to regenerate the epithelium following injury were investigated in mice of different ages. Stem cells from older animals showed an increased apoptotic response following exposure to low doses of ionising radiation. The regenerative capacity was estimated by measuring the crypt survival levels and the growth rate of surviving crypts after high doses of irradiation. Surviving crypts in the older mice, suggesting an impairment in the damage recognition/response mechanisms, were both fewer and smaller than in young mice. The growth rate of surviving crypts was determined by measuring the crypt area and the number of cells/crypt at various times after 14 Gy irradiation. There was a growth delay of between half and one day in the older mice, and they subsequently grew more slowly. The number of cells susceptible to regenerate a crypt was also estimated. Surprisingly, they appear to be more numerous in the older mice. These studies indicate important age-related alterations in the capacity of the stem cells to regenerate the crypts after radiation-induced damage. The molecular bases of these changes are currently being investigated. Preliminary data showed alteration in the level of p53 and p21 expression, suggesting an age-related defect in the capacity to recognize damage and initiate apoptosis or repair.

Characterization of changes in IgG associated oligosaccharide profiles in rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis using fluorophore linked carbohydrate electrophoresis

OBJECTIVE

To investigate fluorophore linked carbohydrate electrophoresis (FCE) as a method of analyzing serum immunoglobulin G (IgG) oligosaccharides in healthy individuals and those with rheumatic disease and compare with lectin binding assays of carbohydrate composition.

METHODS

IgG was isolated from patients with rheumatoid arthritis (RA) (n = 21), ankylosing spondylitis (AS) (n = 20), psoriatic arthritis (PsA) (n = 20), and healthy adults (n = 36). IgG oligosaccharides were released enzymatically, fluorescently labelled using 8 aminonaphthalene-136 trisulfonic acid; and identification of the oligosaccharide bands was by stepwise enzymatic degradation. Comparison of FCE was made with lectin binding analysis in which the lectins Ricinus communis (RCA1) and Bandeiraea simplicifolia (BSII) were used to detect galactose (Gal) and N-acetylglucosamine (GlcNAc), respectively.

RESULTS

Each disease could be differentiated from healthy adults on the basis of Band 1 asialodigalacto core fucosylated oligosaccharide (gf2) intensity (p = 0.001), but not from each other. Reduced levels of different sugars were associated with specific diseases: reduced gf2 with RA (p < 0.001), PsA (p < 0.001) and AS (p < 0.02), reduced Band 5 disialo-digalacto core fucosylated (a2f) oligosaccharide with AS (p < 0.001), reduced Band 6 disialo-digalacto (a2) oligosaccharide with AS (p < 0.001) and PsA (p = 0.021). All diseases were associated with a significant increase in Band 4 asialo-agalacto core fucosylated oligosaccharide (g0f) (p < 0.001). In RA, FCE band intensities correlated with sugar quantity when identified using lectin binding analysis (p < 0.003). In contrast, there was no correlation between the same bands in healthy individuals.

CONCLUSION

FCE is an accurate method of analyzing IgG associated oligosaccharides and reveals unique band patterns or sugar prints associated with healthy adults and patients with RA, PsA, and AS, and comparison with lectin binding analysis suggests undetected RA glycoprotein structural differences. FCE has potential in the early diagnosis and differentiation of rheumatic diseases.

Monitoring the microbial purity of the treated water and dialysate

Dialysate purity has become a major concern in recent years since it has been proven that contamination of dialysate is able to induce the production of proinflammatory cytokines, putatively implicated in the development of dialysis related pathology. In order to reduce this risk, it is advised to use ultrapure dialysate as a new standard of dialysate purity. Ultrapure dialysate preparation may be easily achieved with modern water treatment technologies. The reliable production of ultrapure dialysate requires several prerequisites: use of ultrapure water, use of clean electrolytic concentrates, implementation of ultrafilters in the dialysate pathway to ensure cold sterilization of the fresh dialysate. The regular supply with such high-grade purity dialysate relies on predefined microbiological monitoring of the chain using adequate and sensitive methods, and hygienic handling including frequent disinfection to reduce the level of contamination and to prevent biofilm formation. Reliability of this process requires compliance with a very strict quality assurance process. In this paper, we summarized the principles of the dialysate purity monitoring and the criteria used for surveillance in order to establish good antimicrobial practices in dialysis.

MR diffusion tensor imaging of white matter tract disruption in stroke at 3 T

Recent advances in MR diffusion weighted imaging (DWI) enable the identification of anisotropic white matter tracts with diffusion tensor imaging (DTI). We aimed to use a novel DTI technique to safely study patients with recent stroke in a high field (3 T) MR machine with its intrinsically higher spatial resolution and signal-to-noise ratio. Of ten patients studied, six had disruption of white matter tracts as determined by DTI. A further patient had distortion of white matter tracts around an infarct rather than actual disruption of the tracts themselves. The lack of tract destruction may imply a beneficial prognosis, information that is not available with conventional DWI.

MAPS: a microarray project system for gene expression experiment information and data validation

SUMMARY

MAPS is a MicroArray Project System for management and interpretation of microarray gene expression experiment information and data. Microarray project information is organized to track experiments and results that are: (1) validated by performing analysis on stored replicate gene expression data; and (2) queried according to the biological classifications of genes deposited on microarray chips.

Substance P stimulates inhibitory synaptic transmission in the guinea pig basolateral amygdala in vitro

To determine the physiological role of tachykinin NK1 receptors in the basolateral nucleus of the amygdala (BLN) we have studied the electrophysiological effects of substance P (SP) in the absence and presence of selective tachykinin receptor antagonists in guinea pig brain slices. Recordings were made from two populations of neurones; spiny pyramidal and stellate neurones, both thought to be projection neurones. Activation of NK1 receptors with SP increased the frequency of spontaneous inhibitory postsynaptic potentials in the majority of cells. This effect was blocked by bicuculline or tetrodotoxin, but not ionotropic glutamate receptor antagonists. The enhanced synaptic activity induced by SP was antagonised by the NK1 receptor antagonist L-760,735 but not by the less active enantiomer L-781,773 or the NK3 receptor antagonist L-769,927. Thus in the basolateral nucleus of the guinea pig amygdala, NK1 receptor activation preferentially stimulates inhibitory synaptic activity. Consistent with this observation, immunohistochemistry revealed NK1 receptor immunoreactivity to be largely restricted to a subset of GABA interneurones. These studies support a physiological role for SP in the regulation of pathways involved in the control of emotional behaviour.