Selective localization of oxytocin receptors and vasopressin 1a receptors in the human brainstem

ABSTRACT

Intranasal oxytocin (OT) affects a suite of human social behaviors, including trust, eye contact, and emotion recognition. However, it is unclear where oxytocin receptors (OXTR) and the structurally related vasopressin 1a receptors (AVPR1a) are expressed in the human brain. We have previously described a reliable, pharmacologically informed receptor autoradiography protocol for visualizing these receptors in postmortem primate brain tissue. We used this technique in human brainstem tissue to identify the neural targets of OT and vasopressin. To determine binding selectivity of the OXTR radioligand and AVPR1a radioligand, sections were incubated in four conditions: radioligand alone, radioligand with the selective AVPR1a competitor SR49059, and radioligand with a low or high concentration of the selective OXTR competitor ALS-II-69. We found selective OXTR binding in the spinal trigeminal nucleus, a conserved region of OXTR expression in all primate species investigated to date. We found selective AVPR1a binding in the nucleus prepositus, an area implicated in eye gaze stabilization. The tissue’s postmortem interval (PMI) was not correlated with either the specific or nonspecific binding of either radioligand, indicating that it will not likely be a factor in similar postmortem studies. This study provides critical data for future studies of OXTR and AVPR1a in human brain tissue.

KEYWORDS:

• Brainstem
• receptor autoradiography
• neuropeptides
• spinal trigeminal nucleus
• nucleus prepositus

Acknowledgment

Human tissue was obtained from University of Maryland Brain and Tissue Bank, which is a Brain and Tissue Repository of the NIH Neurobiobank.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the NIH under Grant P51OD011107 to the California National Primate Research Center and by Grant P50MH100023 to A.S.