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Acute administration of lithium carbonate interferes with suckling in neonatal rats
1Department of Psychology, Dartmouth College, Hanover, NH 03755.
Insights
Lithium carbonate administration in rat pups impaired suckling behavior by increasing nipple attachment latency and interfering with milk withdrawal. This animal model helps elucidate lithium
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Clinical observations suggest lithium use during pregnancy may decrease infant suckling.
- The precise mechanisms underlying this phenomenon remain unclear.
- An animal model is needed to investigate lithium's effects on suckling behavior.
Purpose of the Study:
- To establish an animal model for lithium-induced suppression of suckling.
- To determine the causal mechanisms of lithium's effect on suckling in developing rats.
- To investigate how lithium impacts infant's ability to locate nipples and extract milk.
Main Methods:
- Nine-day-old rat pups were administered lithium carbonate via intraperitoneal injection or intragastric gavage.
- Pups were tested for nipple attachment latency to an anesthetized dam.
- Milk extraction was assessed using oxytocin-induced milk letdown.
- Motor and sensory functions were evaluated using open-field and olfactory choice tests.
Main Results:
- Lithium administration significantly increased the latency for rat pups to attach to a nipple.
- Lithium was found to interfere with milk withdrawal, a key component of suckling.
- Lithium did not impair motor or sensory deficits relevant to suckling behavior.
Conclusions:
- This study provides a valid animal model for lithium-induced decrease in suckling.
- Lithium primarily affects the behavioral and milk-extraction aspects of suckling, not motor or sensory abilities.
- The findings suggest specific neural or physiological pathways affected by lithium during early development.
Abstract:
These studies provide an animal model for the lithium-induced decrease in suckling reported in the clinical literature that allows for more precise determination of causal mechanisms. Nine-day-old rat pups were administered lithium carbonate via either intraperitoneal (IP) injections or intragastric (IG) gavage in doses approximating that which human infants might receive via breast milk. The pups were tested for their ability to locate and attach to the nipples of an anesthetized dam. Lithium significantly increased the pups' latency to attach to a nipple. Further tests of milk extraction using oxytocin-induced milk-letdowns indicate that lithium also interferes with milk withdrawal. Tests of motor and sensory deficits using an open-field and an olfactory choice test indicated that lithium did not similarly impair these behavioral facets of suckling. Alternative mechanisms for lithium-produced suppression of suckling are discussed.