Oxytocin Measurement

About: Oxytocin Measurement is a(n) research topic. Over the lifetime, 15 publication(s) have been published within this topic receiving 512 citation(s).

Evaluation of enzyme immunoassay and radioimmunoassay methods for the measurement of plasma oxytocin

Abstract: Objective There is increased interest in measuring peripheral oxytocin levels to better understand the role of this peptide in mammalian behavior, physiology, and disease. The purpose of this study was to compare methods for plasma oxytocin measurement using a commercially available enzyme immunoassay (EIA) and radioimmunoassay (RIA), to evaluate the need for sample extraction, and to assess the immunospecificity of the assays.

Mortyn Jones Memorial Lecture. Intracerebrally released vasopressin and oxytocin: measurement, mechanisms and behavioural consequences.

Abstract: The extracellular fluid (ECF) of the brain contains an as yet unknown number of chemical signals, including neuropeptides, which participate in interneuronal communication. Neuropeptides released within distinct brain areas may act as transmitters and modulators, whereas those released into the systemic circulation act as hormones (Table 1 ). As transmitters, neuropeptides contribute to the synaptic (or wiring) mode of information transfer which refers to fast point-to-point signalling. Apart from its topology, this mode of communication is characterized by relatively short distances, low receptor affinity, and transient actions which are limited to postsynaptic sites. In contrast, volume information transfer is defined as being due to modulators which are non-synaptically released into the ECF and act on relatively distant targets ( 1, 2). Accordingly, this signalling is primarily defined by the chemistry of the modulator and the distribution of its receptors. The brain is liberated from the constraints of neuroanatomical connections through this type of information transfer, since neuropeptides as modulators are released from multiple sites of the neuronal membrane and can reach any point of receptive neurons, thus increasing enormously the informationhandling capacity of neurons. These characteristics explain why a few ‘classical’ neurotransmitters are quite sufficient for the myriads of wired pathways, whereas a large number of different neuropeptides are essential to define volume transmission by their chemistry. Neuropeptides are ideal modulators, in that they can carry much more information than, for example, amino acids or even monoamines as ‘classical’ transmitters. Furthermore, a change in the coding for a neuropeptide results directly in an altered peptide structure. The resulting remarkable diversity of peptide structures provides the potential for generating highly specific actions. Neuropeptides are, in other words, appropriate for experimentation in animals to ascertain their adaption to changes in the environment, thus contributing to evolutionary plasticity (3). The distinction between transmitters, modulators and hormones (Table 1) has its heuristic value. It explains high speed and spatial precision on the one hand up to a theoretically unlimited variability in signalling on the other. Nevertheless, it is illusory to believe that the brain works in this way. Probably even simple information transfers use a combination of these modes of communication, e.g. a neuropeptide molecule released as a transmitter could subsequently act as a modulator suggesting that complex responses to a neuropeptide are likely to reflect a gradation from synaptic through non-synaptic to conventional hormonal actions. It is an attractive notion to compare the complexity and variability of interneuronal communication with our language (4, 5). Accordingly, a phone call and information transfer via a megaphone respectively would reflect wired and volume transmission to a certain extent (as would radio in case of hormone action, Table 1). A promising and necessarily reductive approach to understand the biological ‘language’ of endogenous neuropeptides in the brain is to focus on single ‘words’. To identify what is being said, where the words are coming from, and to understand the informational impact of this ‘language’ requires that, (a) its components (i.e. interpretable sequences of amino acids) are unequivocally identified (e.g. by specific radioimmunoassays); (b) its local dynamics of release are characterized (e.g. by microdialysis), and (c) its biological significance is determined (e.g. by ethologically relevant behavioural tests). Furthermore, one has the opportunity to change the ‘language’ (e.g. by stimulation of intracerebral release or down-regulation of the latter by antisense targeting) and the ‘recipients’ (e.g. by use of antisense to receptor mRNA), and then to measure the consequences. These approaches, therefore, have to reduce the ‘language’ into its component parts without ignoring the fact that understanding single ‘words’ is just the beginning of understanding the ‘language’.

Plasma Oxytocin Immunoreactive Products and Response to Trust in Patients with Social Anxiety Disorder

Abstract: Background Generalized Social Anxiety Disorder (GSAD) is characterized by excessive fear and avoidance of several types of social and performance situations. The pathophysiology is not well understood, but research in animals and humans has provided evidence that oxytocin helps regulate normal social affiliative behavior. Previous work in healthy male subjects demonstrated a rise in plasma oxytocin after receiving a high trust signal. To examine the oxytocin system in GSAD, we measured plasma oxytocin in GSAD patients and controls, before and after the social “Trust Game,” a neuroeconomic test examining trust behavior and reaction to trust using real monetary incentives. Methods Thirty-nine subjects with GSAD and 28 healthy controls provided three blood samples for oxytocin measurement before the Trust Game, and one sample after the game. Plasma estradiol was also measured at baseline. The Trust Game protocol version prioritized the sending of a signal of high cooperation and trust to all participants. All analyses controlled for gender and estradiol levels. Results Mean oxytocin levels post-Trust Game (P = .025), and overall (area under the curve, P = .011) were lower in GSADpatients compared to controls, after controlling for sex and estradiol. There was no significant change in oxytocin levels after the game in either group. Conclusions We report low plasma oxytocin levels in patients with GSAD during a prosocial laboratory task paradigm. Additional research will be important to further examine the relationship between oxytocin and social behavior in GSAD.

Plasma oxytocin concentration and depressive symptoms: a review of current evidence and directions for future research

Abstract: There is substantial recent interest in the role of oxytocin in social and affiliative behaviors-animal models of depression have suggested a link between oxytocin and mood. We reviewed literature to date for evidence of a potential relationship between peripheral oxytocin concentration and depressive symptoms in humans. Pubmed(®) and PsychINFO(®) were searched for biomedical and social sciences literature from 1960 to May 19, 2015 for empirical articles in English involving human subjects focused on the relationship between peripheral oxytocin concentration and depressive symptoms, excluding articles on the oxytocin receptor gene, or involving exogenous (i.e. intranasal) administration of oxytocin. Eight studies meeting criteria were identified and formally reviewed. Studies of pregnant women suggested an inverse relationship between oxytocin level and depressive symptom severity. Findings in nonpregnant women were broadly consistent with the role of oxytocin release in response to stress supported by animal studies. The relationship between oxytocin and depression in men appeared to be in the opposite direction, possibly reflecting the influence of gonadal hormones on oxytocinergic functioning found in other mammalian species. Overall, small sample sizes, heterogeneity in study designs, and other methodological limitations may account for inconsistent findings. Future research utilizing reliable oxytocin measurement protocols including measurements across time, larger sample sizes, and sample homogeneity with respect to multiple possible confounders (age, gender, race and ethnicity, ovarian status among women, and psychosocial context) are needed to elucidate the role of oxytocin in the pathogenesis of depression, and could guide the design of novel pharmacologic agents.

Daily and hourly temporal association between Δ4-androstenedione - induced preterm myometrial contractions and maternal plasma estradiol and oxytocin concentrations in the 0.8 gestation rhesus monkey☆☆☆★★★

Abstract: OBJECTIVE: Our purpose was to investigate the temporal relationship between Δ 4 -androstenedione-induced preterm switching of myometrial activity patterns from contractures to contractions and maternal plasma estradiol and oxytocin concentrations in the 0.8 gestation rhesus monkey. STUDY DESIGN: Eight rhesus monkeys (132 to 136 days' gestation) were instrumented under halothane with femoral artery and vein catheters and uterine electromyogram electrodes. At 138 to 142 days' gestation baseline maternal femoral artery blood samples for estradiol and oxytocin measurement were taken at 30-minute intervals for 7 hours, starting 2 hours before the onset of darkness. The day after baseline sampling a continuous intravenous Δ 4 -androstenedione infusion (0.3 mg · kg -1 · hr -1 in 10% intralipid at 0.25 ml · hr -1 ) was started in four monkeys, while four monkeys were infused intravenously with intralipid alone. The sampling regimen was then repeated at 1 and 3 days after the start of the Δ 4 -androstenedione or intralipid infusion. Contractions were counted and estradiol and oxytocin were measured by radioimmunoassay. RESULTS: Androstenedione promoted a premature nocturnal increase in myometrial contractions in conjunction with an increase in maternal plasma concentrations of estradiol and oxytocin, which were of similar magnitude to those measured in spontaneous term labor. The increase in maternal estradiol preceded the increase in maternal oxytocin levels and myometrial contractions. The onset of the increase in maternal plasma oxytocin was closely associated with the appearance of myometrial contractions after Δ 4 -androstenedione treatment. In contrast, no sustained premature contractions or changes in estradiol and oxytocin occurred in intralipid-treated monkeys. CONCLUSIONS: We conclude that in the 0.8 gestation rhesus monkey (1) the increase in maternal plasma estradiol precedes the increase in maternal plasma oxytocin after Δ 4 -androstenedione treatment and (2) Δ 4 -androstenedione-induced preterm myometrial contractions are closely associated in time with physiologic increases in maternal plasma oxytocin concentrations. (AM J OBSTET GYNECOL 1996;174:1050-5.)