Oxytocin Acetate

Oxytocin Acetate is the synthetic form of the endogenous nonapeptide neurohormone oxytocin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2), incorporating the essential Cys1-Cys6 disulphide bridge that creates the six-residue ring required for OXTR (oxytocin receptor) binding and activation. Produced naturally by hypothalamic PVN and SON magnocellular neurons, oxytocin is released peripherally from the posterior pituitary (driving uterine contraction and milk ejection) and centrally from axon terminals projecting throughout the brain (modulating social behaviour, fear responses, and neuroendocrine functions).

OXTR is a class A Gq/11-coupled GPCR expressed at highest density in the lateral and central amygdala, hippocampal CA2, nucleus accumbens shell, hypothalamus, olfactory bulb, and uterine smooth muscle. Gq/11 coupling activates phospholipase C-beta, generating IP3 (calcium release from ER) and DAG (PKC activation). In uterine smooth muscle, calcium/PKC drives myosin light chain kinase activation and smooth muscle contraction. In amygdala parvalbumin-positive interneurons, OXTR activation increases feedforward inhibition on principal neurons — the circuit mechanism underlying published anxiolytic effects of oxytocin in social fear contexts.

Critical handling requirement unique to Oxytocin Acetate: the Cys1-Cys6 disulphide bridge is essential for OXTR binding — reduction to the linear dithiol form dramatically reduces receptor affinity. Never include reducing agents (DTT, TCEP, beta-mercaptoethanol, glutathione) in buffers used with Oxytocin Acetate. Additionally, avoid strongly oxidising conditions that could promote aberrant disulphide formation with other thiol-containing molecules in the assay system. Use freshly prepared solutions and store aliquots at -20°C in sealed containers minimising oxygen exposure.

Social neuroscience research with Oxytocin Acetate spans: OXTR-mediated amygdala principal neuron excitability modulation (patch-clamp electrophysiology in amygdala slices); hippocampal CA2 social memory circuit research (CA2 neuron firing rate changes, LTP threshold by theta-burst stimulation); nucleus accumbens social reward circuit modulation (fast-scan cyclic voltammetry for dopamine release, calcium imaging); and comparative oxytocin versus vasopressin pharmacology using OXTR-selective antagonist atosiban versus V1a-selective antagonist SR49059 to dissect shared receptor cross-reactivity.

Vasopressin comparative research is particularly relevant given the structural similarity: oxytocin (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2) and AVP (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH2) differ at only positions 3 and 8, yet show divergent receptor selectivity and distinct behavioural profiles. Parallel experiments with both peptides and receptor-selective antagonists establish which biological effects are OXTR-specific versus V1aR-mediated.

For OXTR-mediated amygdala research: acute rat or mouse brain slices (400um coronal, containing amygdala) in ACSF (artificial cerebrospinal fluid, 95% O2/5% CO2, 32°C). Whole-cell patch-clamp of lateral amygdala principal neurons in voltage clamp mode. Apply Oxytocin Acetate (100nM-1uM) via bath perfusion or local puff application. Measure amplitude and frequency of spontaneous IPSCs (sIPSCs) before, during, and after oxytocin application — increased sIPSC frequency indicates activation of GABAergic parvalbumin interneurons expressing OXTR. Confirm OXTR-specificity using atosiban (selective OXTR antagonist, 1uM pre-perfusion). Vasopressin (AVP, 100nM) as comparative control to assess OXTR versus V1aR contributions to observed effects. Never use DTT or reducing agents in ACSF — the disulphide bridge is essential for OXTR binding. MW: 1007.19 g/mol. CAS: 50-56-6. For laboratory and analytical research purposes only.