Black interneuron in top part of figure prevent the

Info icon This preview shows pages 40–44. Sign up to view the full content.

View Full Document Right Arrow Icon
black interneuron in top part of figure) prevent the full responsiveness of steroid-primed neurons (three horizontal neurons in top and bottom halves of figure). Dopamine (small black neuron in lower part of figure) may enhance the responsiveness of those neurons by inhibiting the GABAergic neurons, thereby disinhibiting the relevant output pathways. This increases the probability that a sexually relevant stimulus will elicit a sexual response. Black neurons are active; white neurons (open circles) are inactive. (From Hull et al. [37] , with permission.)
Image of page 40

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
DA in the MPOA as a function of Castration & T Replacement Fig. 3. Extracellular dopamine in the MPOA of male rats during baseline, a precopulatory period (estrous female behind a perforated barrier), and three 6-min periods after the barrier was removed and the animals were free to copulate. All gonadally intact males and all castrates treated with testosterone propionate (200 μg/day) showed a significant increase in dopamine during the precopulatory period and during copulation; all of these animals did copulate. A total of nine of 14 oil-treated 1-week castrates also showed the precopulatory dopamine response and copulated after the barrier was removed. The remaining 1-week and all four 2-week oil-treated castrates failed to show the precopulatory dopamine response and failed to copulate; data from these two groups are combined. , P<0.05 compared to ϕ final baseline for intact males; , P<0.01 compared to final ϕϕ baseline for intact males; +, P<0.05 compared to final baseline for castrates treated with 200 μg testosterone propionate; *, P<0.05 compared to final baseline for 1-week vehicle-treated castrates that copulated; **, P<0.01 compared to final baseline for 1-week vehicle-treated castrates that copulated; #, P<0.05 compared to final baseline for vehicle-treated castrates that failed to copulate. (From Hull et al. [36], with permission.)
Image of page 41
NOS is necessary to induce DA release in the MPOA Fig. 6. Levels of extracellular dopamine in the MPOA of animals treated with an inhibitor of nitric oxide synthase (l-NAME) or its inactive isomer (d-NAME). l-NAME prevented the increase in dopamine release during copulation that was observed in animals treated with d-NAME. (From Lorrain et al. [49] , with permission.)
Image of page 42

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Glutamate-Dopamine Interactions in mPOA during copulation. Model showing possible interactions between glutamate, nitric oxide (NO), and dopamine in the MPOA. (1) Glutamate (GLUT; gray hexagon) activates NMDA receptors, which opens calcium channels. (2) The resultant increase in intracellular calcium (gray diamonds) then activates calmodulin (CaM), (3) which in turn activates the enzyme NO synthase (NOS); this leads to an immediate production of NO. NOS links to the carboxy-terminal tail of the NMDA receptor, via a PSD-95 protein–protein interaction domain. Once synthesized, NO freely diffuses from cell to cell, (4) where it can alter activity in the presynaptic neurons. (5) Additionally, in dopamine-producing neurons, NO has been shown to inhibit the dopamine transporter (DAT) (6) and increase calcium-dependent and/or calcium-independent vesicular release. Therefore, increased NO in the MPOA, after glutamate release, would increase levels of extracellular dopamine and prolong the presence of dopamine in the synapse. Hull & Dominguez, 2006.
Image of page 43
Image of page 44
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern