Enhancement of Proopiomelanocortin Gene Promoter Activity by Local Anesthetics in a Pituitary Cell Line:

The human POMC gene promoter: where do we stand?

Proopiomelanocortin (POMC) is crucial for several life-essential functions and its regulation has been studied extensively in the past decades. The first studies provided the framework for POMC promoter activity, namely the identification for the major response elements contained in the promoter, e.g., the glucocorticoid response element, the Nur response element, while subsequent studies showed the importance of cooperation and interplay between transcription factors to achieve optimal promoter activity. The involvement of constitutive repressors of POMC transcription, such as Bmp4, provided the latest clues to our understanding of POMC promoter activity. This increased knowledge benefits the clinician as it allows genetic testing and early recognition of patients with congenital ACTH deficiency due to mutations in TPIT and paves the way to new medical treatments in Cushing's disease. The present review will illustrate the current standing on regulation of the human POMC promoter, focusing on its activity in corticotropes.

Long-term intrathecal morphine and bupivacaine upregulate MOR gene expression in lymphocytes

BACKGROUND

Several studies have shown that opioids may suppress the immune system either by binding to mu-opioid receptors (MOR) expressed in immune cells or by activating these receptors within the central nervous system.

OBJECTIVE

To assess the level of lymphocyte expression of MOR mRNA in patients with chronic non-cancer pain, who were treated with intrathecal morphine or with morphine plus bupivacaine via an intrathecal drug delivery system, and to investigate whether intrathecal morphine and the associated local anesthetic administration influences lymphocyte subpopulations.

METHODS

In total, 29 people [10 controls (age range 59-85 years) and 19 patients (age range 47-89 years) with various chronic non-malignant pain conditions] were enrolled in the study. MOR mRNA levels were evaluated in peripheral lymphocytes, and lymphocyte subsets were determined by direct immunofluorescence using flow cytometry.

RESULTS

After 12 months of treatment with intrathecal morphine (1.5-4 mg/day), there was an increase in MOR mRNA levels in lymphocytes of 65% compared with controls and 47% with pretreatment values. Even higher levels (increase of 142% compared with controls and 135% with pretreatment values) were observed in the patients treated with morphine plus bupivacaine (0.2-0.4 mg/day). Elevation of MOR mRNA levels was confirmed in patients after 24 months of treatment. At this time point, the percentage of natural killer cells was significantly decreased.

CONCLUSION

This preliminary study suggests that opioids must be used with care in patients who are already immunosuppressed by disease or by other, concurrently administered drugs.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.