Acute and Chronic Stress and the Inflammatory Response in Hyperprolactinemic Rats

Abstract

Background/Aim: Prolactin (PRL), a hormone produced by the pituitary gland, has multiple physiological functions, including immunoregulation. PRL can also be secreted in response to stressful stimuli. During stress, PRL has been suggested to oppose the immunosuppressive effects of inflammatory mediators. Therefore, the aim of the present study was to analyze the effects of short- and long-term hyperprolactinemia on the inflammatory response in rats subjected to acute or chronic cold stress. Methods: Inflammatory edema was induced by carrageenan in male rats, and hyperprolactinemia was induced by injections of the dopamine receptor antagonist domperidone. The volume of inflammatory edema was measured by plethysmography after carrageenan injection. Additionally, the effects of hyperprolactinemia on body weight and serum corticosterone levels were evaluated. Results and Conclusion: Five days of domperidone-induced hyperprolactinemia increased the volume of inflammatory edema. No differences in serum corticosterone levels were observed between groups. No significant differences were found among 30 days domperidone-induced hyperprolactinemic animals subjected to acute stress and the inflammatory response observed in chronic hyperprolactinemic animals subjected to chronic stress. The results suggest that short-term hyperprolactinemia has pro-inflammatory effects. Because such an effect was not observed in long-term hyperprolactinemic animals, PRL-induced tolerance seems likely. We suggest that short-term hyperprolactinemia may act as a protective factor in rats subjected to acute stress. These data suggest that hyperprolactinemia and stress interact differentially according to the time period.

Short-Term Hyperprolactinemia Reduces the Expression of Purinergic P2X7 Receptors during Allergic Inflammatory Response of the Lungs

“…Although domperidone does not cross the blood-brain barrier [34], it acts on hypophysis and increases PRL secretion [35-37]. Domperidone was administered at a dose of 1.7 mg × kg– – (i.p.)…”

“…Domperidone was administered at a dose of 1.7 mg × kg– – (i.p.) 3 times per day (6: 30 a.m., 2: 00 p.m., and 9: 00 p.m., therefore a total of 5.1 mg × kg –1 per day) for 5 consecutive days from the 10th to 14th day after OVA immunization [13, 37, 38]. This treatment protocol has effectively produced stable hyperprolactinemia for more than 30 days [13, 39].…”

Dual Effects of Hyperprolactinemia on Carrageenan-Induced Inflammatory Paw Edema in Rats

“…Domperidone was administered at a dose of 1.7 mg/kg (s.c.) 3 times per day (07.30, 15.00 and 22.00 h). The duration of treatment was 8 consecutive days or 33 consecutive days [23] .…”

“…Because such an effect was not observed in long-term hyperprolactinemic animals, PRL-induced tolerance seems likely. Those data suggested that short-term hyperprolactinemia may act as a protective factor in rats subjected to acute stress, and that hyperprolactinemia and stress interact differentially according to the time elapsed [23] .…”

<b>Influência do LPS e do zinco na interação mãe e filhote</b>

“…Foi proposto que a presença de altos níveis de prolactina nas ratas lactantes estaria associada a esta atenuação uma vez que a prolactina tem efeitos supressivos na inflamação (SUGIURA et al, 2012;NASCIMENTO et al, 2013;OCHOA-AMAYA et al, 2015). Para investigar essa hipótese, neste trabalho, ratas virgens foram tratadas com domperidona por 5 dias, um esquema de tratamento que promove hiperprolactinemia (NASELLO et al, 1997;OCHOA-AMAYA et al, 2010 LENCZOWSKI et al, 1999).…”