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Haloperidol Inhibits Maternal Retrieval and Licking, but Enhances Nursing Behavior and Litter Weight Gains in Lactating Rats
Author(s) -
Stern Judith M.,
Taylor Lisa A.
Publication year - 1991
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.1991.tb00323.x
Subject(s) - haloperidol , licking , litter , antagonist , dopamine antagonist , endocrinology , medicine , weight gain , dopamine , zoology , chemistry , psychology , biology , body weight , receptor , ecology
To determine whether the motorically‐active and ‐inactive components of maternal behavior in rats are differentially affected by dopamine, we administered haloperidol, a dopamine receptor antagonist, to lactating rats on day 7 (±1) post‐partum, 3 h after dam‐litter separation and 1 h before their reunion. Compared to treatment with saline or domperidone, a peripherally‐active dopamine antagonist, haloperidol treatment inhibited retrieval and licking of pups in a dose‐dependent manner and hastened the onset of nursing behavior, but impaired the high crouch posture at the highest doses (8 and 10 mg/kg). Also, litters of dams treated with 0.2, 0.4, or 1.0 mg/kg haloperidol gained almost twice as much weight as litters of controls or of dams treated with 5 to 10 mg/ kg haloperidol. To determine whether the milk ejection pattern accounts for differential litter weight gain after moderate and high doses of haloperidol, milk ejections were assessed by pup stretch and nipple‐switching responses for 30 min after the onset of crouching following a 4 h dam‐litter separation on day 12 or 13 post‐partum. The litters of dams treated with 1 or 3 mg/kg haloperidol had substantially greater litter weight gains than litters of control dams or of dams treated with 5 mg/kg haloperidol. The smaller litter weight gain of 5 mg/kg haloperidol litters was due to a retardation of milk ejections in their dams, while the smaller gain of control litters was due, at least in part, to greater behavioral activation by their dams. Non‐dopaminergic effects of large doses of haloperidol (≥5 mg/kg) may have reduced the display of the high crouching posture during nursing and contributed to the retardation of milk ejections. Thus, dopamine is necessary for the motorically‐active components of maternal behavior, but its inhibition may be necessary for the assumption of the immobile nursing postures and for maximal litter weight gains. We hypothesize that extra‐hypothalamic as well as tuberoinfundibular dopaminergic systems are inactivated by the suckling stimulus.