title: Dopamine is involved in the different patterns of copulatory behaviour of Roman high and low avoidance rats: studies with apomorphine and haloperidol.
abstract: Outbred Roman high- (RHA) and low-avoidance (RLA) rats, originally selected for rapid vs. poor acquisition of active avoidance in a shuttle box, show differential copulatory patterns when exposed to a receptive female. Indeed, in the first copulation test male RHA rats show more mounts, intromissions and ejaculations than RLA rats. Such differences do not disappear in subsequent copulation tests, with sexually experienced RHA rats always showing higher levels of sexual motivation and performance than their RLA counterparts. This study shows that the different copulatory patterns of sexually experienced RHA and RLA rats are differentially facilitated by apomorphine, a mixed D1/D2-like dopamine receptor agonist, and impaired by haloperidol, a D2-like dopamine receptor antagonist, given at doses which facilitate and impair, respectively, copulatory behaviour in Sprague Dawley rats used as an external reference strain. Accordingly, apomorphine-induced facilitation and haloperidol-induced impairment of copulatory behaviour were more robust in RLA than RHA rats, as indicated by their effects on several copulatory parameters including mount, intromission and ejaculation latencies, mount, intromission and ejaculation frequencies, post ejaculatory interval, inter-intromission interval and copulatory efficacy. Pretreatment with haloperidol also reduced the facilitatory effect of apomorphine more effectively in RLA than RHA rats. These results suggest that the different copulatory patterns of RHA and RLA rats are mainly due to a lower dopaminergic tone at level of the mesolimbic and incerto-hypothalamic dopaminergic systems of RLA vs. RHA rats, which play a key role in sexual behaviour.
authors: Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, and Centre of Excellence for the Neurobiology of Addictions, University of Cagliari, Monserrato, Cagliari, Italy. Electronic address: fabrizio.sanna@unica.it.
authors: Fabrizio
authors: F
authors: Sanna
authors: Department of Life and Environmental Sciences, Section of Pharmaceutical, Pharmacological and Nutraceutical Sciences, University of Cagliari, 09124, Cagliari, Italy.
authors: Maria Antonietta
authors: MA
authors: Piludu
authors: Department of Life and Environmental Sciences, Section of Pharmaceutical, Pharmacological and Nutraceutical Sciences, University of Cagliari, 09124, Cagliari, Italy.
authors: Maria Giuseppa
authors: MG
authors: Corda
authors: Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, and Centre of Excellence for the Neurobiology of Addictions, University of Cagliari, Monserrato, Cagliari, Italy; Institute of Neuroscience, National Research Council, Cagliari Section, 09042 Monserrato, Cagliari, Italy.
authors: Antonio
authors: A
authors: Argiolas
authors: Department of Life and Environmental Sciences, Section of Pharmaceutical, Pharmacological and Nutraceutical Sciences, University of Cagliari, 09124, Cagliari, Italy.
authors: Osvaldo
authors: O
authors: Giorgi
authors: Department of Biomedical Sciences, Section of Neuroscience and Clinical Pharmacology, and Centre of Excellence for the Neurobiology of Addictions, University of Cagliari, Monserrato, Cagliari, Italy.
authors: Maria Rosaria
authors: MR
authors: Melis
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001362:Avoidance Learning; D003307:Copulation / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D051381:Rats
chemical_list: D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine
keywords: Apomorphine; Copulatory behaviour; Dopamine; Haloperidol; RHA rats; RLA rats