The effect of food and water deprivation on post-stress analgesia in mice and levels of beta-endorphin and dynorphin in blood plasma and hypothalamus

Abstract

Pain sensitivity of food and/or water-deprived male mice was tested on a hotplate. The most pronounced analgesia ensued in animals given no food and water, and no food but water ad libitum, the least one in water-deprived mice. The magnitude of the rise in pain threshold depended on the duration of deprivation and was correlated with the increase in the blood plasma beta-endorphin level. In the hypothalamus beta-endorphin level increased after 72-h food deprivation only. The level of dynorphin remained unchanged. Naloxone (10 mg/kg) almost completely reversed food or water-deprivation induced analgesia.

The Contributions of Mu-Opioid Receptors on Glutamatergic and GABAergic Neurons to Analgesia Induced by Various Stress Intensities

“…In fact, the mismatch between the expression of opioid-dependent analgesia and enhancement levels of β-EP occurs frequently in several stress paradigms ( Scallet, 1982 ; Izquierdo et al, 1984 ; Konecka et al, 1985 ; Külling et al, 1988 ). Just 24 h of food deprivation could significantly promote concentrations of β-EP twice the basal level in mice blood plasma, whereas significant analgesia needs food deprivation for 48 h without a further change in β-EP concentration ( Konecka et al, 1985 ). In addition, MOR-dependent analgesia induced by social conflict needs aggressive confrontation between two populations of mice, but mere exposure of a test mouse to a nonaggressive opponent also provokes the changing of β-EP levels in pain-related brain areas ( Külling et al, 1988 ).…”

“…In general, moderate stress produces opioid analgesia and heavy stress produces nonopioid analgesia, whereas weak stress hardly produces any analgesic effect ( Konecka et al, 1985 ; Miczek et al, 1985 ; Mogil et al, 1996 ). Several types of stressors in moderate intensity like restraint/immobilization, footshock or tailshock, forced swim, food and water deprivation, social isolation, and social conflict, that have been shown to trigger opioid-dependent stress-induced analgesia occur with naloxone (an opioid receptor antagonist) sensitivity ( Konecka et al, 1985 ; Miczek et al, 1985 ; Menendez et al, 1993 ; Mogil et al, 1996 ; Larauche et al, 2012 ). Mu-opioid receptors (MORs), one of the four major opioid receptors encoded by OPRM1 gene, play a critical role in opioid-dependent stress-induced analgesia ( Fukunaga and Kishioka, 2000 ).…”

“…The expression of MOR-dependent stress-induced analgesia is closely associated with the elevated β-endorphin (β-EP) levels. β-EP, one of EOPs that has the highest binding affinity for MORs and is synthesized immediately in the early period of stress ( Konecka et al, 1985 ; Tsigos and Chrousos, 2002 ; Smith and Vale, 2006 ; Bodnar, 2013 ; Pilozzi et al, 2020 ). The significant rise of β-EP concentrations in blood plasma and several pain-related brain areas like hypothalamus, pituitary gland, and PAG have been clearly observed in various stress paradigms including food and water deprivation and social conflict ( Konecka et al, 1985 ; Külling et al, 1988 ).…”

“…β-EP, one of EOPs that has the highest binding affinity for MORs and is synthesized immediately in the early period of stress ( Konecka et al, 1985 ; Tsigos and Chrousos, 2002 ; Smith and Vale, 2006 ; Bodnar, 2013 ; Pilozzi et al, 2020 ). The significant rise of β-EP concentrations in blood plasma and several pain-related brain areas like hypothalamus, pituitary gland, and PAG have been clearly observed in various stress paradigms including food and water deprivation and social conflict ( Konecka et al, 1985 ; Külling et al, 1988 ). Mice with low β-EP sensitivity exhibit a decrease in pain threshold compared with normal β-EP sensitivity when exposed to swim stress ( Lim and Funder, 1983 ).…”

The effect of water deprivation on shock-escape impairment after exposure to inescapable shock

“…Water deprivation manipulations have also been shown to increase the pain threshold in mice as assessed by a hot plate test (Konecka, Sroczynska, & Przewlocki, 1985). Because naltrexone abolished this effect, it is assumed that water deprivation recruits an opioid response.…”