Showing papers by "Daniela Parolaro published in 2003"
TL;DR: It is demonstrated that prolonged activation of opioid receptors could alter the cannabinoid system, in terms of both receptor functionality and endocannabinoid levels, and suggest the involvement of this system, alone or in combination with other mediators, in the phenomenon of morphine tolerance.
81 citations
TL;DR: Cellular events induced by morphine pre-exposure could underlie the neuroadaptive processes involved in morphine sensitization and the main second messenger system linked to the opioid receptor is the cAMP pathway.
70 citations
TL;DR: In this article, the authors investigated the cellular events linked to the induction of cannabinoid behavioural sensitization in sensitized rats and found that only two brain areas had altered receptor functionality, namely the caudate putamen and cerebellum.
Abstract: We investigated the cellular events linked to the induction of cannabinoid behavioural sensitization. In sensitized rats, autoradiographic binding studies with [3H]CP-55,940 showed a significant increase in cannabinoid receptor binding, specifically in the cerebellum, with no changes in the other brain areas where basal CB1-receptor expression is observed. In vitro autoradiography of CP-55,940-stimulated [35S]GTP gamma S binding provided a picture of cannabinoid receptor-mediated G protein activation. Basal [35S]GTP gamma S binding was not affected, whereas sensitized rats showed a significant increase of net [35S]GTP gamma S binding in the caudate putamen and cerebellum. Autoradiographic studies suggested that only these two areas had altered receptor functionality. We therefore focused our intracellular investigations only there, first surveying the responsiveness of the cAMP system to cannabinoids. CP-55,940 was unable to inhibit forskolin-induced cAMP accumulation in the cerebellum of sensitized animals, but no difference was observed between groups in the caudate putamen. Finally, we surveyed the levels of CREB and AP-1 binding activity, in the same two areas and found no difference in sensitized rats. The intracellular picture in sensitized rats suggests that besides the cAMP cascade, other signalling pathways may participate in the development of cannabinoid sensitization.
30 citations
TL;DR: Data indicate for the first time that the organisation of the mu-opioid receptor system in the brain, as well as a differential vulnerability to abuse of opiate drugs can be modulated by epigenetic variables such as the prenatal in utero contiguity to male foetuses.
24 citations
TL;DR: The hypothesis of cAMP as part of the common intracellular pathway shared by opiates and cannabinoids at immune cell level is strengthened.
15 citations