Urinary and plasma oxytocin changes in response to MDMA or intranasal oxytocin administration.

BACKGROUND: The neuropeptide oxytocin (OT) has received increased experimental attention for its putative role in both normal social functioning and several psychiatric disorders that are partially characterized by social dysfunction (e.g., autism spectrum disorders: ASD). Many human experimental studies measure circulating plasma levels of OT in order to examine the relationship between the hormone and behavior. Urinary OT (uOT) assays offer a simple, easy, and non-invasive method to measure peripheral hormone levels, but the correspondence between uOT and plasma OT (pOT) levels is unclear. Here, we conducted two within-subjects, double-blind studies exploring changes in uOT and pOT levels following administration of two drugs: MDMA, an oxytocin-releasing drug (Study 1), and intranasal oxytocin (INOT: Study 1 and 2). METHODS: In Study 1, 14 adult participants (2 females) were each administered either oral 1.5mg/kg MDMA or 40IU INOT across two different study sessions. In Study 2, 10 male participants (adolescents and young adults) diagnosed with ASD received either 40IU INOT or placebo across two different sessions. In both studies, blood and urine samples were collected before and after drug administration at each study session. For Study 1, 10 participants provided valid plasma and urine samples for the MDMA session, and 8 provided valid samples for the INOT session. For Study 2, all 10 participants provided valid samples for both INOT and placebo sessions. Pre- and post-administration levels of pOT and uOT were compared. Additionally, correlations between percent change from baseline uOT and pOT levels were examined. RESULTS: Study 1: Plasma OT and uOT levels significantly increased after administration of MDMA and INOT. Furthermore, uOT levels were positively correlated with pOT levels following administration of MDMA (r=0.57, p=0.042) but not INOT (r=0.51, p=0.097). Study 2: There was a significant increase in uOT levels after administration of INOT, but not after administration of placebo. Under both conditions, INOT and placebo, significant increases in pOT levels were not observed. Additionally, change from baseline uOT and pOT levels were positively correlated (r=0.57, p=0.021). There was no significant correlation between uOT and pOT levels following placebo administration. CONCLUSION: Our results show a measurable and significant increase in pOT and uOT levels after the administration of MDMA (Study 1) and INOT (Study 1 and Study 2). Additionally, a positive correlation between uOT and pOT levels was observed in both samples (healthy adults and ASD patients) in at least one condition. However, uOT and pOT levels were not correlated under all conditions, suggesting that uOT levels do not fully correspond to pOT levels in the time windows we measured. Future studies should further examine the relationship between levels of pOT and uOT in healthy and clinical populations on measures of social behavior because uOT may serve as an additional non-invasive method to measure peripheral OT changes.

Changes in urine levels of substance P, vasoactive intestinal peptide and calcitonin-gene-related peptide in patients with urinary tract infections.

Urinary tract infections (UTI) are important health problems and predisposing causes of UTI are not entirely known. Neuro-immune interactions play an important role in human health and disease. Capsaicin-sensitive sensory nerves which in nerve bladder extensively regulate immune system through neuropeptides such as substance P (SP), calcitonin-gene related peptide (CGRP) and vasoactive intestinal peptide (VIP). In addition these neuropeptides also have anti-bacterial effects. To determine how the levels of these peptides changes during UTI, 67 patients (50-90 years-old) diagnosed with UTI in Akdeniz University Faculty of Medicine Hospital were compared with 37 healthy people 50 years or older as the control group. Additionally, 7 patients with UTI symptoms (dysuria, urgency) but with sterile pyuria were also included in the study. Urine samples from 15 patients, whose symptoms regressed with control urine cultures being sterile, were taken after completion of the treatments. Urine neuropeptide levels were determined by ELISA. CGRP levels are significantly higher in patients with UTI, but did not associate with pyuria whereas SP and VIP levels were significantly lower in patients with sterile pyuria, indicating sensory nerve deficiency. Since CGRP exerts immunosuppressive effects, increased levels of the peptide may predispose to UTI. Furthermore, the connection between the observed sensory nerve deficiency and sterile pyuria warrants further studies.

Activity regulates functional connectivity from the vomeronasal organ to the accessory olfactory bulb.

The mammalian accessory olfactory system is specialized for the detection of chemicals that identify kin and conspecifics. Vomeronasal sensory neurons (VSNs) residing in the vomeronasal organ project axons to the accessory olfactory bulb (AOB), where they form synapses with principal neurons known as mitral cells. The organization of this projection is quite precise and is believed to be essential for appropriate function of this system. However, how this precise connectivity is established is unknown. We show here that in mice the vomeronasal duct is open at birth, allowing external chemical stimuli access to sensory neurons, and that these sensory neurons are capable of releasing neurotransmitter to downstream neurons as early as the first postnatal day (P). Using major histocompatibility complex class I peptides to activate a selective subset of VSNs during the first few postnatal days of development, we show that increased activity results in exuberant VSN axonal projections and a delay in axonal coalescence into well defined glomeruli in the AOB. Finally, we show that mitral cell dendritic refinement occurs just after the coalescence of presynaptic axons. Such a mechanism may allow the formation of precise connectivity with specific glomeruli that receive input from sensory neurons expressing the same receptor type.

Urinary biomarkers trefoil factor 3 and albumin enable early detection of kidney tubular injury.

The capacities of urinary trefoil factor 3 (TFF3) and urinary albumin to detect acute renal tubular injury have never been evaluated with sufficient statistical rigor to permit their use in regulated drug development instead of the current preclinical biomarkers serum creatinine (SCr) and blood urea nitrogen (BUN). Working with rats, we found that urinary TFF3 protein levels were markedly reduced, and urinary albumin were markedly increased in response to renal tubular injury. Urinary TFF3 levels did not respond to nonrenal toxicants, and urinary albumin faithfully reflected alterations in renal function. In situ hybridization localized TFF3 expression in tubules of the outer stripe of the outer medulla. Albumin outperformed either SCr or BUN for detecting kidney tubule injury and TFF3 augmented the potential of BUN and SCr to detect kidney damage. Use of urinary TFF3 and albumin will enable more sensitive and robust diagnosis of acute renal tubular injury than traditional biomarkers.

Autism and urinary exogenous neuropeptides: development of an on-line SPE-HPLC-tandem mass spectrometry method to test the opioid excess theory.

Autism is a complex neurodevelopmental disorder with unknown etiology. One hypothesis regarding etiology in autism is the "opioid peptide excess" theory that postulates that excessive amounts of exogenous opioid-like peptides derived from dietary proteins are detectable in urine and that these compounds may be pathophysiologically important in autism. A selective LC-MS/MS method was developed to analyze gliadinomorphin, beta-casomorphin, deltorphin 1, and deltorphin 2 in urine. The method is based on on-line SPE extraction of the neuropeptides from urine, column switching, and subsequent HPLC analysis. A limit of detection of 0.25 ng/mL was achieved for all analytes. Analyte recovery rates from urine ranged between 78% and 94%, with relative standard deviations of 0.2-6.8%. The method was used to screen 69 urine samples from children with and without autism spectrum disorders for the occurrence of neuropeptides. The target neuropeptides were not detected above the detection limit in either sample set.

Expression of orexin-A and orexin receptors in the kidney and the presence of orexin-A-like immunoreactivity in human urine.

Orexin-A (hypocretin-1), a neuropeptide with stimulatory actions on arousal and appetite, was originally shown to be specifically expressed in the hypothalamus. We studied expression of orexin-A and orexin receptors in the kidney and the presence of orexin-A-like immunoreactivity in human urine. Immunocytochemistry showed that orexin-A-like immunoreactivity and two types of orexin receptors (types 1 and 2) were localized in the tubules of the human kidney obtained at autopsy. Orexin-A-like immunoreactivity was detected in human kidneys (21.3 +/- 6.2 fmol/g wet weight, mean +/- S.E.M., n = 4) and rat kidneys (16.2 +/- 1.6 fmol/g wet weight, n = 5) by radioimmunoassay, although the levels were much lower than the levels in the brain. Orexin-A-like immunoreactivity was present in the urine obtained from male healthy volunteers (67.8 +/- 4.5 pmol/l, n = 5). Reverse phase high-performance liquid chromatography showed that most of orexin-A-like immunoreactivity of the urine extract was eluted earlier than authentic orexin-A, suggesting that orexin-A-like immunoreactivity in urine was modified to hydrophilic forms. Reverse transcriptase polymerase chain reaction showed expression of orexin receptors 1 and 2 mRNAs in the human kidney. These findings suggest that orexin-A is produced by the renal tubular cells and secreted into urine. Orexin-A may act on the kidney in the autocrine or paracrine fashion, or via the urine (urocrine fashion).

Early experience in humans is associated with changes in neuropeptides critical for regulating social behavior.

The formation of social attachments is a critical component of human relationships. Infants begin to bond to their caregivers from the moment of birth, and these social bonds continue to provide regulatory emotional functions throughout adulthood. It is difficult to examine the interactions between social experience and the biological origins of these complex behaviors because children undergo both brain development and accumulate social experience at the same time. We had a rare opportunity to examine children who were reared in extremely aberrant social environments where they were deprived of the kind of care-giving typical for our species. The present experiment in nature provides insight into the role of early experience on the brain systems underlying the development of emotional behavior. These data indicate that the vasopressin and oxytocin neuropeptide systems, which are critical in the establishment of social bonds and the regulation of emotional behaviors, are affected by early social experience. The results of this experiment suggest a potential mechanism whose atypical function may explain the pervasive social and emotional difficulties observed in many children who have experienced aberrant care-giving. The present findings are consistent with the view that there is a critical role for early experience in the development of the brain systems underlying basic aspects of human social behavior.

N-acetylaspartylglutamate in Canavan disease: an adverse effector?

UNLABELLED: We measured N-acetylaspartate and its precursor/product N-acetylaspartylglutamate (NAAG) in urine of patients with Canavan disease using capillary zone electrophoresis. Abnormal levels of NAAG were found in 32 of 43 patients examined. Elevated NAAG was also present in the CSF of one patient. Given that NAAG may interfere with N-methyl-D-aspartate receptor function, the occurrence of high levels of NAAG in patients' urine conceivably represents a participating factor in the pathogenesis of Canavan disease. CONCLUSION: The biochemical role of N-acetylaspartylglutamate and its relationship to glutamatergic function may be relevant to the pathogenesis of Canavan disease.

Pharmacokinetics and brain entry of alaptide, a novel nootropic agent, in mice, rats and rabbits.

Pharmacokinetics of a novel nootropic agent, alaptide, have been examined in plasma and brain of mice, rats and rabbits following an intravenous dose (1 mg kg-1). First-order equilibration rate constants between plasma and brain (kBO) were calculated by a two-compartment model with a linked compartment (brain). Brain alaptide equilibrates rapidly with the central compartment in mice and rats due to the high kBO/beta ratio. In rabbits the equilibration is much slower (kBO/beta approximately 1). Partition coefficients between brain and plasma calculated from areas under the brain and plasma concentration-time curves, are 0.479, 0.549 and 0.864, in mice, rats and rabbits, respectively.

Urinary chromatographic profiles in schizophrenia.

In a series of articles, Trygstad et al. (1980) suggested that specific patterns of peptide excretion and increased levels of peptide material are found by chromatographic analysis of the urine of patients with a variety of psychiatric illness including schizophrenia. As these results have not been independently replicated in another laboratory, we conducted an investigation of urine samples from 5 DSM-III classified schizophrenic patients and 4 normal subjects using the techniques described by the Norwegian group, and with a series of modifications. The chromatographic profiles obtained differ widely from those reported by Trygstad et al. No significant differences were detected between patients with schizophrenia and controls. The methods used by Trygstad et al. are complex and we have defined several parts of the methods which are subject to variability. Our findings lend no support to the view that patients with psychiatric illness can be readily distinguished from normal subjects by the amount or profile of peptide excretion in urine.