“…However, oxytocin likely produces central changes that affect downstream processes such as autonomic outflow and behavioral responses to isolation. While circulating oxytocin is purported to cross the blood-brain barrier in small quantities (approximately 0.2% of subcutaneously administered oxytocin crosses the blood-brain barrier in adult rodents) (see Jones and Robinson, 1982; Ermisch et al, 1985), chronic peripheral administration of this peptide produces many of the same responses that occur following central release of oxytocin, including reductions in blood pressure and regulation of motivated behaviors (Arletti et al, 1992; Petersson et al, 1996; Caldwell et al, 1996; Liberzon et al, 1997). Similarly, peripheral administration of oxytocin in rats has been shown to alter receptor function in central regions associated with stressor responsiveness and cardiovascular regulation, including hypothalamus, amygdala, NTS, and locus coeruleus (Petersson et al, 1998; 2005).…”