Fair M Vassoler1, Anika M Toorie2, Elizabeth M Byrnes2. 1. Tufts University Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA, 01536, USA. Fair.vassoler@tufts.edu. 2. Tufts University Cummings School of Veterinary Medicine, 200 Westboro Road, North Grafton, MA, 01536, USA.
Abstract
RATIONALE: A growing body of evidence demonstrates that environmental exposures can impact the physiology and behavior of subsequent generations. We have previously demonstrated reduced morphine self-administration in the F1 and F2 offspring of female rats exposed to morphine during adolescence. OBJECTIVES: The current study was designed to determine whether attenuated self-administration for a substance not in the opioid class is also observed in the F1 progeny of adolescent morphine exposed females. METHODS: Female adolescent rats were administered morphine at increasing doses for 10 days (P30-39). Females then remained drug free for at least 3 weeks prior to mating with drug-naïve males. As adults, male and female offspring (F1 animals) were tested for cocaine self-administration acquisition, progressive ratio, extinction, and reinstatement. In addition, β-endorphin peptide levels were measured in the nucleus accumbens (NAc) of behaviorally experienced animals following reinstatement and in behaviorally naïve littermates after acute cocaine (0 or 10 mg/kg, i.p.). Proopiomelanocortin, the polypeptide that is cleaved to produce β-endorphin, as well as β-endorphin, was examined in the arcuate nucleus of the hypothalamus and the nucleus accumbens, respectively. Finally, corticosterone was measured following acute cocaine. RESULTS: While no differences were observed during the cocaine acquisition phase (FR-1 and FR-5 schedules), under a PR schedule, Mor-F1 animals (both males and females) had increased motivated responding for cocaine. In addition, Mor-F1 males demonstrated enhanced reinstatement compared to Sal-F1 males. In Mor-F1 males, an acute injection of cocaine (10 mg/kg, i.p.) decreased β-endorphin levels in the NAc compared to a saline injection while acute cocaine increased β-endorphin in the NAc in Sal-F1 males compared to saline injection. Following acute cocaine, Mor-F1 males had significantly lower levels of β-endorphin in the Nac compared to Sal-F1 males. Additionally, β-endorphin levels in the nucleus accumbens were negatively correlated with reinstatement behavior only in Mor-F1 males. Levels of POMC in the arcuate nucleus were elevated in Mor-F1 males compared to Sal-F1 males, a main effect driven primarily by POMC levels in the acute cocaine condition. These changes were not observed in Mor-F1 females. Finally, plasma corticosterone was increased in Mor-F1 males regardless of acute injection while Mor-F1 females displayed increased corticosterone in response to acute cocaine. CONCLUSIONS: These data indicate that morphine prior to conception increases the rewarding effects of cocaine in male and female offspring. In addition, sex-specific alterations in endogenous opioids and hypothalamic physiology were observed.
RATIONALE: A growing body of evidence demonstrates that environmental exposures can impact the physiology and behavior of subsequent generations. We have previously demonstrated reduced morphine self-administration in the F1 and F2 offspring of female rats exposed to morphine during adolescence. OBJECTIVES: The current study was designed to determine whether attenuated self-administration for a substance not in the opioid class is also observed in the F1 progeny of adolescent morphine exposed females. METHODS: Female adolescent rats were administered morphine at increasing doses for 10 days (P30-39). Females then remained drug free for at least 3 weeks prior to mating with drug-naïve males. As adults, male and female offspring (F1 animals) were tested for cocaine self-administration acquisition, progressive ratio, extinction, and reinstatement. In addition, β-endorphin peptide levels were measured in the nucleus accumbens (NAc) of behaviorally experienced animals following reinstatement and in behaviorally naïve littermates after acute cocaine (0 or 10 mg/kg, i.p.). Proopiomelanocortin, the polypeptide that is cleaved to produce β-endorphin, as well as β-endorphin, was examined in the arcuate nucleus of the hypothalamus and the nucleus accumbens, respectively. Finally, corticosterone was measured following acute cocaine. RESULTS: While no differences were observed during the cocaine acquisition phase (FR-1 and FR-5 schedules), under a PR schedule, Mor-F1 animals (both males and females) had increased motivated responding for cocaine. In addition, Mor-F1 males demonstrated enhanced reinstatement compared to Sal-F1 males. In Mor-F1 males, an acute injection of cocaine (10 mg/kg, i.p.) decreased β-endorphin levels in the NAc compared to a saline injection while acute cocaine increased β-endorphin in the NAc in Sal-F1 males compared to saline injection. Following acute cocaine, Mor-F1 males had significantly lower levels of β-endorphin in the Nac compared to Sal-F1 males. Additionally, β-endorphin levels in the nucleus accumbens were negatively correlated with reinstatement behavior only in Mor-F1 males. Levels of POMC in the arcuate nucleus were elevated in Mor-F1 males compared to Sal-F1 males, a main effect driven primarily by POMC levels in the acute cocaine condition. These changes were not observed in Mor-F1 females. Finally, plasma corticosterone was increased in Mor-F1 males regardless of acute injection while Mor-F1 females displayed increased corticosterone in response to acute cocaine. CONCLUSIONS: These data indicate that morphine prior to conception increases the rewarding effects of cocaine in male and female offspring. In addition, sex-specific alterations in endogenous opioids and hypothalamic physiology were observed.
Authors: Bruno Fant; Mathieu E Wimmer; Sarah E Swinford-Jackson; John Maurer; Duncan Van Nest; R Christopher Pierce Journal: Psychopharmacology (Berl) Date: 2019-06-25 Impact factor: 4.530
Authors: Fair M Vassoler; Anika M Toorie; Delaney N Teceno; Pankhuri Walia; Deion J Moore; Trevor D Patton; Elizabeth M Byrnes Journal: Neuropharmacology Date: 2019-11-11 Impact factor: 5.250
Authors: Anika M Toorie; Fair M Vassoler; Fangfang Qu; Christopher M Schonhoff; Steven Bradburn; Christopher A Murgatroyd; Donna K Slonim; Elizabeth M Byrnes Journal: Addict Biol Date: 2019-11-28 Impact factor: 4.280
Authors: Annalisa M Baratta; Richa S Rathod; Sonja L Plasil; Amit Seth; Gregg E Homanics Journal: Int Rev Neurobiol Date: 2020-09-30 Impact factor: 3.230
Authors: Anika M Toorie; Fair M Vassoler; Fangfang Qu; Donna Slonim; Christopher M Schonhoff; Elizabeth M Byrnes Journal: Sci Rep Date: 2022-01-31 Impact factor: 4.379