Here is a study that compared the differences in distribution patterns and regional quantities of oxytocin (OT) and/or vasopressin (AVP) staining in the forebrains of wild and laboratory strains of rats and mice. The investigators did find differential expression patterns and their results “suggest that domestication significantly alters the expression of OT and AVP in related brain areas of laboratory rats and mice, an observation that could explain the identified changes in behavioral patterns.”

Title: Laboratory domestication changed the expression patterns of oxytocin and vasopressin in brains of rats and mice.

Reference: Anat Sci Int. 2016 Sep;91(4):358-70.

PMID: 26553093

Dear Itzik, this paper shows the effects of nasal administration of oxytocin in C57BL/6 and BALB mice. Social approach was increased in C57BL/6 mice, but not in BALB mice, a low sociability strain. Oxytocin exerts differential effects depending on the mouse strain.

Article Involvement of serotonin and oxytocin in neural mechanism re...

Dear Raffaele d'Isa and Brian Pike

Thank you so much for you answers, I know this comes late but I posted this question in several sites and didn't follow up in all of them, so I apologize for that.

We tried to increased sociability of C57 mice by IP administration of oxytocin, but didn't get any increase, so this paper will really help!

Dear Itzik, you may be interested also in the following paper:

Article Effects of intraperitoneal and intracerebroventricular injec...

Sakamoto and colleagues found that, in male C57BL/6J mice, an intraperitoneal injection of a high dose of oxytocin (1 mg/kg) reduced social interaction with a novel mouse or a cagemate mouse. On the other hand, a low dose (0.1 mg/kg) had no effect.