Zachary A Grieb1,2, Erika M Vitale3, Joan I Morrell4, Joseph S Lonstein5,3, Mariana Pereira4,6. 1. Neuroscience Program, Michigan State University, 108 Giltner Hall, East Lansing, MI, 48824, USA. zgrieb1@gsu.edu. 2. Neuroscience Institute, Georgia State University, 880 Petit Science Center, Atlanta, GA, 30303, USA. zgrieb1@gsu.edu. 3. Department of Psychology, Behavioral Neuroscience Program, Michigan State University, 316 Physics Rd, East Lansing, MI, 48824, USA. 4. Center for Molecular and Behavioral Neuroscience, Rutgers University, 197 University Avenue, Newark, NJ, 07102, USA. 5. Neuroscience Program, Michigan State University, 108 Giltner Hall, East Lansing, MI, 48824, USA. 6. Department of Psychological and Brain Sciences, University of Massachusetts, 535 Tobin Hall, Amherst, MA, 01003, USA.
Abstract
RATIONALE: Mesolimbic dopamine (DA) signaling is essential for the high maternal caregiving characteristic of the early postpartum period, but little is known about dopamine's role in the expression of maternal caregiving thereafter. OBJECTIVES: We tested the hypothesis that decreased mesolimbic dopaminergic signaling is particularly responsible for the natural decline in maternal caregiving that occurs as the postpartum period progresses. METHODS: Sprague-Dawley (SD) mother rats received intraperitoneal injections of either vehicle, the DA D1 receptor agonist SKF38393, the DA D2 receptor agonist quinpirole, or both agonists twice daily from postpartum days 9 to 15. In a separate experiment involving Long-Evans (LE) rats, we examined whether DA D1 and D2 receptor mRNAs in the nucleus accumbens (NA) shell and ventral tegmental area (VTA), along with DA turnover in the VTA, decline across the postpartum period in parallel with the decreasing maternal behavior. RESULTS: All drug treatments significantly maintained higher frequencies of active maternal behaviors (nesting, pup licking, retrieval) compared to vehicle. Furthermore, the majority of mothers treated with SKF38393 either alone or combined with quinpirole maintained full expression of maternal behavior during behavioral testing. D2 receptor mRNA levels were found to be lower in the late postpartum NA shell and VTA compared to early postpartum, but D1 receptor mRNA levels in the NA shell were higher in the late postpartum period. Furthermore, both late postpartum and recently parturient LE mothers had higher VTA DA turnover compared to nulliparae, suggesting changes in mesolimbic signal-to-noise ratio both at the end and beginning of motherhood. CONCLUSIONS: Collectively, our results suggest that alterations in mesolimbic DA is part of the neural substrate responsible for dynamic maternal caregiving across the entire postpartum period.
RATIONALE: Mesolimbic dopamine (DA) signaling is essential for the high maternal caregiving characteristic of the early postpartum period, but little is known about dopamine's role in the expression of maternal caregiving thereafter. OBJECTIVES: We tested the hypothesis that decreased mesolimbic dopaminergic signaling is particularly responsible for the natural decline in maternal caregiving that occurs as the postpartum period progresses. METHODS: Sprague-Dawley (SD) mother rats received intraperitoneal injections of either vehicle, the DA D1 receptor agonist SKF38393, the DA D2 receptor agonist quinpirole, or both agonists twice daily from postpartum days 9 to 15. In a separate experiment involving Long-Evans (LE) rats, we examined whether DA D1 and D2 receptor mRNAs in the nucleus accumbens (NA) shell and ventral tegmental area (VTA), along with DA turnover in the VTA, decline across the postpartum period in parallel with the decreasing maternal behavior. RESULTS: All drug treatments significantly maintained higher frequencies of active maternal behaviors (nesting, pup licking, retrieval) compared to vehicle. Furthermore, the majority of mothers treated with SKF38393 either alone or combined with quinpirole maintained full expression of maternal behavior during behavioral testing. D2 receptor mRNA levels were found to be lower in the late postpartum NA shell and VTA compared to early postpartum, but D1 receptor mRNA levels in the NA shell were higher in the late postpartum period. Furthermore, both late postpartum and recently parturient LE mothers had higher VTA DA turnover compared to nulliparae, suggesting changes in mesolimbic signal-to-noise ratio both at the end and beginning of motherhood. CONCLUSIONS: Collectively, our results suggest that alterations in mesolimbic DA is part of the neural substrate responsible for dynamic maternal caregiving across the entire postpartum period.
Entities:
Keywords:
Dopamine; Maternal behavior; Motivation; Nucleus accumbens; Ventral tegmental area
Authors: Selena E Bartlett; Johan Enquist; Frederic W Hopf; Josephine H Lee; Fredrik Gladher; Viktor Kharazia; Maria Waldhoer; William S Mailliard; Randall Armstrong; Antonello Bonci; Jennifer L Whistler Journal: Proc Natl Acad Sci U S A Date: 2005-07-27 Impact factor: 11.205
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Authors: Zachary A Grieb; Emma G Ford; Mahircan Yagan; Billy Y B Lau; Fredric P Manfredsson; Keerthi Krishnan; Joseph S Lonstein Journal: Psychoneuroendocrinology Date: 2021-06-18 Impact factor: 4.693