Detection of basal levels and induction of delta opioid receptor mRNA in murine splenocytes

Activation of delta opioid receptors (DOR) modulates calcium mobilization, interleukin-2 production, chemotaxis and proliferation of T-lymphocytes. Recent reports indicate that lymphocytes and mononuclear cells may express mRNA transcripts for DOR. The investigations reported herein show that low levels of DOR were consistently detected by RT-PCR amplification of RNA from freshly obtained Balb/c murine splenocytes, both weanling and adult. Culturing cells without stimulation increased DOR levels and concanavalin A apparently reduced this; DOR was preferentially expressed in a T-cell-enriched fraction. Thus, the expression of DOR mRNA by unactivated splenocytes is modulated by culture and con A in the T-cell fraction.