Tyrosine hydroxylase in the ventral tegmental area of rams with high or low libido-A role for dopamine
| Autor: | Brenda M. Alexander, Kathy J. Austin, Charles E. Roselli, A.C. Kramer, A.J. Mirto |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Male medicine.medical_specialty Hydrocortisone Tyrosine 3-Monooxygenase Dopamine Libido Dopamine Agents Biology Gene Expression Regulation Enzymologic Article 03 medical and health sciences Sexual Behavior Animal 0302 clinical medicine Endocrinology Blood serum Food Animals Internal medicine Dopamine receptor D2 medicine Animals Tyrosine Cells Cultured Estrous cycle Neurons Sheep Tyrosine hydroxylase Receptors Dopamine D2 Ventral Tegmental Area General Medicine Ventral tegmental area 030104 developmental biology medicine.anatomical_structure nervous system Forebrain Animal Science and Zoology Female 030217 neurology & neurosurgery medicine.drug |
| Zdroj: | Animal reproduction science. 187 |
| ISSN: | 1873-2232 |
| Popis: | Dopamine synthesis in the ventral tegmental area (VTA) is necessary for the reinforcement of sexual behavior. The objective of this study determined if sexual stimuli initiates reward, and whether reward is attenuated in sexually inactive rams. Sexually active rams were exposed to urine from estrous (n = 4) or ovariectomized (n = 3) ewes with inactive rams (n = 3) exposed to urine from estrous ewes. Following exposure, rams were exsanguinated and brains perfused. Alternating sections of the VTA were stained for Fos related antigens (FRA), tyrosine hydroxylase, and dopamine beta-hydroxylase activity. Forebrain tissue, mid-sagittal ventral to the anterior corpus callosum, was stained for dopamine D(2) receptors. Concentrations of cortisol was determined prior to and following exposure. Exposure to ovariectomized-ewe urine in sexually active rams did not influence (P = 0.6) FRA expression, but fewer (P < 0.05) neurons were positive for tyrosine hydroxylase in the VTA. Sexually inactive rams had fewer (P < 0.05) FRA and tyrosine hydroxylase positive neurons in the VTA than sexually active rams following exposure to estrous ewe urine. VTA neurons staining positive for dopamine beta-hydroxylase did not differ by sexual activity (P = 0.44) or urine exposure (P = 0.07). Exposure to stimulus did not influence (P = 0.46) numbers of forebrain neurons staining positive for dopamine D2 receptors in sexually active rams, but fewer (P = 0.04) neurons stain positive in inactive rams. Serum concentrations of cortisol did not differ (P ≥ 0.52) among rams prior to or following stimulus. In conclusion sexual inactivity is unlikely due to stress, but may be partially a result of decreased tyrosine hydroxylase and/or the response to dopamine. |
| Databáze: | OpenAIRE |
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