1. Neonatal exposure to oestradiol increases dopaminergic transmission in nucleus accumbens and morphine-induced conditioned place preference in adult female rats
- Author
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A. Martorell, María Estela Andrés, Victoria B. Velásquez, M. V. Selva, Ramón Sotomayor-Zárate, Roxana A. Silva, Gonzalo Cruz, Pedro Espinosa, Jonathan Martínez-Pinto, Pablo R. Moya, and Christian Bonansco
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Dopamine ,Nucleus accumbens ,Biology ,Synaptic Transmission ,Nucleus Accumbens ,Rats, Sprague-Dawley ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,0302 clinical medicine ,Endocrinology ,Neurochemical ,Internal medicine ,medicine ,Animals ,Neurotransmitter ,Neurons ,Estradiol ,Morphine ,Endocrine and Autonomic Systems ,Dopaminergic Neurons ,Dopaminergic ,Estrogens ,Conditioned place preference ,Prolactin ,Rats ,Analgesics, Opioid ,030104 developmental biology ,nervous system ,chemistry ,Conditioning, Operant ,Female ,030217 neurology & neurosurgery ,Hormone ,medicine.drug - Abstract
Steroid sex hormones produce physiological effects in reproductive tissues and also in nonreproductive tissues, such as the brain, particularly in cortical, limbic and midbrain areas. Dopamine (DA) neurones involved in processes such as prolactin secretion (tuberoinfundibular system), motor circuit regulation (nigrostriatal system) and driving of motivated behaviour (mesocorticolimbic system) are specially regulated by sex hormones. Indeed, sex hormones promote neurochemical and behavioural effects induced by drugs of abuse by tuning midbrain DA neurones in adult animals. However, the long-term effects induced by neonatal exposure to sex hormones on dopaminergic neurotransmission have not been fully studied. The present study aimed to determine whether a single neonatal exposure with oestradiol valerate (EV) results in a programming of dopaminergic neurotransmission in the nucleus accumbens (NAcc) of adult female rats. To answer this question, electrophysiological, neurochemical, cellular, molecular and behavioural techniques were used. The data show that frequency but not amplitude of the spontaneous excitatory postsynaptic current is significantly increased in NAcc medium spiny neurones of EV-treated rats. In addition, DA content and release are both increased in the NAcc of EV-treated rats, caused by an increased synthesis of this neurotransmitter. These results are functionally associated with a higher percentage of EV-treated rats conditioned to morphine, a drug of abuse, compared to controls. In conclusion, neonatal programming with oestradiol increases NAcc dopaminergic neurotransmission in adulthood, which may be associated with increased reinforcing effects of drugs of abuse.
- Published
- 2017