Oxytocin

Oxytocin Receptor Distribution and Function

The oxytocin receptor (OTR) is a Gq-coupled GPCR expressed in:

Limbic system:

• Amygdala (basolateral, central nuclei) - fear and threat processing
• Hippocampus - social memory formation
• Nucleus accumbens - social reward

Hypothalamus:

• PVN (autoreceptor function)
• Lateral hypothalamus - appetite modulation

Brainstem:

• Locus coeruleus - stress response modulation
• Dorsal raphe - serotonin interaction

OTR activation in the amygdala reduces threat-responsive neuronal firing, which manifests behaviourally as reduced social anxiety and enhanced prosocial motivation.

The 2005 Nature Study and Its Context

The Kosfeld et al. paper demonstrating that intranasal oxytocin increases trust in economic games made oxytocin famous as the “trust hormone.” However, the subsequent decade of research produced a more nuanced picture:

• Trust enhancement is strongest for in-group/similar social targets
• Context dependency: oxytocin can increase both trust and vigilance depending on social context
• Individual differences in OTR polymorphisms (rs53576) predict response
• Baseline peripheral oxytocin predicts social cognition in both typical and ASD populations

Autism Research Status

The most rigorous meta-analyses of intranasal oxytocin in ASD (as of 2023) show:

• Positive: Some improvement in social cognition tasks in laboratory settings
• Inconsistent: Mixed results across RCTs for real-world social function
• Active question: Whether dose, duration (acute vs chronic), or participant selection drives variability
• Consensus: More targeted studies with biomarker-defined subgroups are needed

Storage

Reconstitution: use bacteriostatic water; swirl gently until dissolved, do not shake. Protect from light. After reconstitution: keep refrigerated and use within 2-3 weeks.

For research purposes only. Not for human consumption.