Tactile stimulation modulates withdrawal-related behaviors and brain molecular parameters in male offspring following...

The opioid crisis has intensified over recent decades, largely driven by the widespread and often indiscriminate prescription of opioid analgesics for chronic pain, leading to an unprecedented global burden of opioid-related morbidity and mortality. In this context, maternal opioid use represents a critical source of neurodevelopmental vulnerability for exposed offspring, irrespective of the occurrence of neonatal withdrawal, which develops in only a subset of opioid-exposed infants. This highlights the urgent need to elucidate the neurobiological mechanisms of dependence at birth and to identify early interventions capable of mitigating withdrawal and preventing long-term consequences. By promoting neuroplasticity, tactile stimulation (TS) represents a promising early-life intervention for recovery from withdrawal-related symptoms and dysfunctions after early opioid exposure. To investigate this, pregnant rats received escalating doses of morphine throughout gestation and lactation, while male offspring were exposed to early-life TS until weaning, followed by behavioral assessment of withdrawal-related responses. Moreover, molecular analyses of addiction- and neuroplasticity-related markers in brain reward and hedonic circuits were performed. Maternal exposure to morphine increased withdrawal-related behavioral responses in the offspring, whereas early-life TS effectively attenuated these alterations, restoring the overall withdrawal behavioral profile. At the molecular level, perinatal morphine disrupted dopaminergic and glutamatergic signaling in the Nucleus accumbens, as evidenced by the modulation of D1-R, D2-R, GLUA1-R, DAT and ΔFosB levels. Notably, TS reversed these neurochemical alterations, restoring molecular marker levels toward baseline values. Together, these findings support TS as a non-invasive intervention with the potential to mitigate neonatal abstinence syndrome, modulate addiction-related neuroplasticity, and support neurodevelopment in infants exposed to opioids during early life.