Gonadal hormones regulate the expression of α 1 -adrenoceptor subtypes in several tissues. The present study was carried out to determine whether or not cyproterone acetate, an anti-androgenic agent, regulates the α 1 -adrenoceptor subtypes that mediate contractions of the rat vas deferens in response to noradrenaline. The actions of subtype selective α 1 -antagonists were investigated in vas deferens from control and cyproterone acetate-treated rats (10 mg/day, sc, for 7 days). Prazosin (pA 2 ≈9.5), phentolamine (pA 2 ≈8.3) and yohimbine (pA 2 ≈6.7) presented competitive antagonism consistent with activation of α 1 -adrenoceptors in vas deferens from both control and treated rats. The pA 2 values estimated for WB 4101 (≈9.5), benoxathian (≈9.7), 5-methylurapidil (≈8.5), indoramin (≈8.7) and BMY 7378 (≈6.8) indicate that α 1A -adrenoceptors are involved in the contractions of the vas deferens from control and cyproterone acetate-treated rats. Treatment of the vas deferens from control rats with the α 1B /α 1D -adrenoceptor alkylating agent chloroethylclonidine had no effect on noradrenaline contractions, supporting the involvement of the α 1A -subtype. However, this agent partially inhibited the contractions of vas deferens from cyproterone acetate-treated rats, suggesting involvement of multiple receptor subtypes. To further investigate this, the actions of WB 4101 and chloroethylclonidine were reevaluated in the vas deferens from rats treated with cyproterone acetate for 14 days. In these organs WB 4101 presented complex antagonism characterized by a Schild plot with a slope different from unity (0.65 ± 0.05). After treatment with chloroethylclonidine, the complex antagonism presented by WB 4101 was converted into classical competitive antagonism, consistent with participation of α 1A -adrenoceptors as well as α 1B -adrenoceptors. These results suggest that cyproterone acetate induces plasticity in the α 1 -adrenoceptor subtypes involved in the contractions of the vas deferens.

The entorhinal cortex (EC) is associated with impaired cognitive function such as in the case of Alzheimer's disease, Parkinson's disease and Huntington's disease. The present study provides a detailed analysis of the cytoarchitectural and myeloarchitectural organization of the EC in the common marmoset Callithrix jacchus. Data were collected using Nissl and fiber stained preparations, supplemented with acetylcholinesterase and parvalbumin immunohistochemistry. The EC layers and subfields in the marmoset seem to be architectonically similar to those that have been proposed in nonhuman primates and humans to date; however, slight differences could be revealed using the present techniques. Throughout its rostrocaudal length, the entorhinal cortex presents a clear six‐layered pattern. The entorhinal cortex is divided into six fields, named mainly in accordance to their rostrocaudal and mediolateral positions. At rostral levels, the neurons tend to be organized in patches that are surrounded by large, thick, radially oriented bundles of fibers, and the deep layers are poorly developed. At caudal levels, the divisions are more laminated in appearance. AChE staining at the borders of adjacent fields are consistent with the changes in layering revealed in Nissl‐stained sections, of which the lateral regions of the EC display denser AChE staining than that of the medial banks. PV immunoreactivity was found in the labeled somata, dendrites, and axons in all layers and subdivisions. Additionally, we distinguished three subtypes of PV‐immunoreactive neurons: multipolar, bipolar and spherical‐shaped neurons, based on the shape of the somata and the disposition of the dendrites.

This study was aimed at establishing the subcorticals substrates of the cognitive and visceromotor circuits of the A32 and A25 cortices of the medial prefrontal cortex and their projections and interactions with subcortical complexes in the common marmoset monkey (Callithrix jacchus). The study was primarily restricted to the nuclei of the diencephalon and amygdala. The common marmoset is a neotropical primate of the new world, and the absence of telencephalic gyrus favors the mapping of neuronal fibers. The biotinylated dextran amine was employed as an anterograde tracer. There was an evident pattern of rostrocaudal distribution of fibers within the subcortical nuclei, with medial orientation. Considering this distribution, fibers originating from the A25 cortex were found to be more clustered in the diencephalon and amygdala than those originating in the A32 cortex. Most areas of the amygdala received fibers from both cortices. In the diencephalon, all regions received projections from the A32, while the A25 fibers were restricted to the thalamus, hypothalamus, and epithalamus at different densities. Precise deposits of neuronal tracers provided here may significantly contribute to expand our understanding of specific connectivity among the medial prefrontal cortex with limbic regions and diencephalic areas, key elements to the viscerocognitive process.

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