The goal of the present investigation was to study a full dose-response of quinpirole in production of species-specific 50 kHz ultrasonic vocalizations in rats, and to study involvement of D2 and D3 dopamine receptors in this response. Quinpirole, a D2/D3 dopamine agonist with high selectivity for D2 dopamine receptors, was injected into the shell of the nucleus accumbens. Quinpirole induced species-specific 50 kHz ultrasonic vocalizations at a wide range of doses as compared to saline. The dose-response study showed a triphasic effect of quinpirole and reached two comparable peak responses in the number of emitted vocalizations at 0.25 μg and 6 μg, respectively (a 24-fold dose difference). These two peaks were separated by a decreased phase. A medium dose range (0.5-1.0 μg) of quinpirole consistently depressed production of calls to the control level. Application of antagonists of D2 dopamine receptors (raclopride) and D3 dopamine receptors (U-99194A) before quinpirole revealed that quinpirole activates differentially the D2 and D3 dopamine receptors at different doses. The vocalization response induced by the low dose of quinpirole (0.25 μg) was antagonized by local pretreatment with the D3 receptor antagonist but not by the D2 receptor antagonist. On the other hand, the response induced by the high dose of quinpirole (6 μg) was antagonized by a similar local pretreatment with the D2 receptor antagonist but not by the D3 receptor antagonist. In conclusion, the results indicated that quinpirole can induce 50 kHz vocalizations after its direct intra-accumbens application in rats, and both D2 and D3 dopamine receptors are involved in the response. They play, however, different functional roles, as revealed by the triphasic effect of increasing doses of quinpirole.
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http://dx.doi.org/10.1016/j.bbr.2011.10.004 | DOI Listing |
Insect Biochem Mol Biol
January 2025
Department of Vector Entomology, Kyungpook National University, Sangju, Republic of Korea; Research Institute of Invertebrate Vector, Kyungpook National University, Sangju, Republic of Korea. Electronic address:
Dopamine plays multifaceted roles in the physiology of insects and ticks, acting as a key neurotransmitter and modulator of various biological processes. In ticks, it plays a particularly important role in regulating salivary gland function, which is essential for successful tick feeding on hosts. Salivary secretion in ticks is orchestrated by the collection of saliva in the acinar lumen mediated by the dopamine receptor (D1) and the expulsion of collected saliva into the salivary duct mediated by the invertebrate specific D1-like dopamine receptor (InvD1L).
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January 2025
Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, 16132 Genova, Italy.
Acromegaly is a rare endocrine disorder caused by excessive growth hormone (GH) production, due, in the vast majority of cases, to the presence of a GH-secreting pituitary tumour. The chronic elevation of GH and the resulting high circulating levels of insulin-like growth factor-1 (IGF-1) cause the characteristic tissue overgrowth and a number of associated comorbidities, including several metabolic changes, such as glucose intolerance and overt diabetes mellitus (DM). Elevated GH concentrations directly attenuate insulin signalling and stimulate lipolysis, decreasing glucose uptake in peripheral tissues, thus leading to the development of impaired glucose tolerance and DM.
View Article and Find Full Text PDFBiomolecules
December 2024
Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2G3, Canada.
Schizophrenia is a complex heterogenous disorder thought to be caused by interactions between genetic and environmental factors. The theories developed to explain the etiology of schizophrenia have focused largely on the dysfunction of neurotransmitters such as dopamine, serotonin and glutamate with their receptors, although research in the past several decades has indicated strongly that other factors are also involved and that the role of neuroglial cells in psychotic disorders including schizophrenia should be given more attention. Although glia were originally thought to be present in the brain only to support neurons in a physical, metabolic and nutritional capacity, it has become apparent that these cells have a variety of important physiological roles and that abnormalities in their function may make significant contributions to the symptoms of schizophrenia.
View Article and Find Full Text PDFBiomedicines
December 2024
Institute of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
Dopamine receptors (DRs) are G-protein-coupled receptors (GPCRs) found in the central nervous system (CNS). DRs are essential for mediating various downstream signaling cascades and play a critical role in regulating the dopaminergic nigrostriatal pathway, which is involved in motor control. Recently, mutations in DRD2 (WT), p.
View Article and Find Full Text PDFSci Rep
January 2025
Pharmacy Discipline, Life Science School, Khulna University, Khulna, 9208, Bangladesh.
Dopamine receptor D4 (DRD4) plays a vital role in regulating various physiological functions, including attention, impulse control, and sleep, as well as being associated with various neurological diseases, including attention deficit hyperactivity disorder, novelty seeking, and so on. However, a comprehensive analysis of harmful nonsynonymous single nucleotide polymorphisms (nsSNPs) of the DRD4 gene and their effects remains unexplored. The aim of this study is to uncover novel damaging missense nsSNPs and their structural and functional effects on the DRD4 receptor.
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