The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko

Smeets, Wilhelmus J. A. J.; Pérez–Clausell, Jeús; Geneser, Finn A.

doi:10.1007/bf00321899

Cited by 63 publications

(76 citation statements)

References 45 publications

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“…lez & Smeets, 1993 ; Marı! n et al 1998 a), a condition similar to that observed in reptiles (Smeets & Steinbusch, 1989 ;Smeets, 1994) and birds .…”

Section: Striatopallidal Systemsmentioning

confidence: 53%

Evolution of the basal ganglia: new perspectives through a comparative approach

2000

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The basal ganglia (BG) have received much attention during the last 3 decades mainly because of their clinical relevance. Our understanding of their structure, organisation and function in terms of chemoarchitecture, compartmentalisation, connections and receptor localisation has increased equally. Most of the research has been focused on the mammalian BG, but a considerable number of studies have been carried out in nonmammalian vertebrates, in particular reptiles and birds. The BG of the latter 2 classes of vertebrates, which together with mammals constitute the amniotic vertebrates, have been thoroughly studied by means of tract-tracing and immunohistochemical techniques. The terminology used for amniotic BG structures has frequently been adopted to indicate putative corresponding structures in the brain of anamniotes, i.e. amphibians and fishes, but data for such a comparison were, until recently, almost totally lacking. It has been proposed several times that the occurrence of well developed BG structures probably constitutes a landmark in the anamniote-amniote transition. However, our recent studies of connections, chemoarchitecture and development of the basal forebrain of amphibians have revealed that tetrapod vertebrates share a common pattern of BG organisation. This pattern includes the existence of dorsal and ventral striatopallidal systems, reciprocal connections between the striatopallidal complex and the diencephalic and mesencephalic basal plate (striatonigral and nigrostriatal projections), and descending pathways from the striatopallidal system to the midbrain tectum and reticular formation. The connectional similarities are paralleled by similarities in the distribution of chemical markers of striatal and pallidal structures such as dopamine, substance P and enkephalin, as well as by similarities in development and expression of homeobox genes. On the other hand, a major evolutionary trend is the progressive involvement of the cortex in the processing of the thalamic sensory information relayed to the BG of tetrapods. By using the comparative approach, new insights have been gained with respect to certain features of the BG of vertebrates in general, such as the segmental organisation of the midbrain dopaminergic cell groups, the occurrence of large numbers of dopaminergic cell bodies within the telencephalon itself and the variability in, among others, connectivity and chemoarchitecture. However, the intriguing question whether the basal forebrain organisation of nontetrapods differs essentially from that observed in tetrapods still needs to be answered.

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“…lez & Smeets, 1993 ; Marı! n et al 1998 a), a condition similar to that observed in reptiles (Smeets & Steinbusch, 1989 ;Smeets, 1994) and birds .…”

Section: Striatopallidal Systemsmentioning

confidence: 53%

Evolution of the basal ganglia: new perspectives through a comparative approach

2000

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“…Using a cryostat (Microm HM 500 OM), 200-μm coronal sections were thaw mounted onto Superfrost Plus slides (Erie Scientific, USA). Sections were then rapidly frozen using a cooling block set at −20°C (Physitemp Instruments Inc., USA), and the POA was dissected using a 300-μm diameter micropunch, as per Smeets and Steinbusch (1988) and Young et al (1994). Tissue samples from each animal were assayed independently of each other and not pooled.…”

Section: Tissue Collection For Hplc Analysismentioning

confidence: 99%

Serotonergic modulation of male-like pseudocopulatory behavior in the parthenogenetic whiptail lizard, Cnemidophorus uniparens

Dias

Crews

2006

Hormones and Behavior

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Hormone-neurotransmitter interactions form an important link through which hormones influence a variety of behavioral processes. Typically, sexual behavior is dimorphic with males mounting receptive females. In the all-female lizard species Cnemidophorus uniparens, individuals display both male-like pseudocopulation and female-like receptivity. These respective behavioral states are correlated with high circulating concentrations of progesterone following ovulation and of estrogen preceding it. In sexual species, serotonin is involved in male-typical mounting, and, as reported here, in male-like pseudosexual behavior in this unisexual species. In the first study, C. uniparens were ovariectomized and treated systemically with exogenous androgen, a hormonal regimen that results in individuals displaying only male-like pseudosexual behavior. An increase in serotonin levels in the preoptic area coupled with the suppression of male-like pseudocopulation was observed in androgen-treated lizards injected with 5-hydroxytryptophan (the precursor of serotonin) and clorgyline (a monoamine oxidase inhibitor) compared to vehicle-treated controls. Our second experiment involved ovariectomizing lizards and either injecting them with estradiol or implanting them with either an empty (Blank) or a progesterone-or testosterone-containing Silastic capsule. Treatment with para-chlorophenylalanine (an inhibitor of tryptophan hydroxylase) facilitated malelike pseudosexual behavior depending on the circulating hormonal milieu and decreased serotonin levels in the preoptic area. Our data suggest that serotonin is inhibitory to male-like pseudosexual behavior in C. uniparens but more importantly that the hormonal environment modulates the serotonin system at the level of the preoptic area, with the serotonergic system then establishing behavioral thresholds that allow for this behavior to be "gated".

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“…Recent histochemical studies have revealed the distribution of the serotonergic (Smeets and Steinbusch, 1988) and noradrenergic fibers (Smeets and Steinbusch, 1989) within the NS. The distribution patterns of these fibers are similar to those of the AC fibers observed in the Golgi preparations.…”

Section: Discussionmentioning

confidence: 99%

“…The efferent connections of the NS have been reported by several authors (Halpern and Silfen, 1974;Hoogland, 1977;Voneida and Sligar, 1979;Halpern, 1980;Stoll and Hoogland, 1984), while systematic analysis of its intrinsic organization has been more limited (Ulinski and Kanarek, 1973). Recently, the distribution of various chemicals in reptilian brains has been studied histochemically (Smeets et al , 1986;Perez-Clausell, 1988; Smeets, 1988;Smeets and Steinbusch, 1988;. Further information on the structure of the NS is needed.…”

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confidence: 98%

A Golgi Study on the Nucleus Sphericus of the Striated Snake, Elaphe quadrivirgata

Iwahori

Nakamura

Tsuda

1995

Okajimas Folia Anatomica Japonica

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Sununary: The intrinsic organization of the nucleus sphericus (NS) was studied in the striated snake using the rapid Golgi method. The NS is a large aggregation of cells located in the posterior portion of the telencephalon and is, as a whole, cupshaped with its hilus oriented in the rostral direction. From the periphery inward, the following three concentric layers were discernible: a marginal layer, mural layer and hilar layer. The marginal layer consists of scattered cells extending dendrites internally toward the hilar layer and externally into the anterior commissure (AC). The mural layer contains densely packed polygonal neurons with dendrites extending internally into the hilar layer and externally toward the marginal layer. The hilar layer consists of scattered cells whose dendrites extend in a transverse direction, distributing mainly in the hilar layer. The axons of the neurons in the marginal and mural layers travel rostromedially, and some axons can be traced into the AC, while those of the neurons in the hilar layer run rostrally, and some are lost among fibers of the accessory olfactory tract (AOT). The afferents to the NS are derived mainly from the AOT and AC. The AOT fibers travel caudally in a thick bundle through the hilus and are distributed totally within the hilar layer, forming a dense fiber plexus. The AC fibers enter the nucleus from the rostromedial aspect and run in an arched course, emitting numerous fine short collaterals.The nucleus sphericus (NS) is a prominent cellular aggregation located in the caudal portion of the telencephalon in certain families of reptiles, and is known to be one of the main terminal areas of the accessory olfactory tract (AOT) (Heimer, 1969;Halpern, 1976;1980;Ulinski and Peterson, 1981;Martinez-Garcia et al. 1991). From a hodological viewpoint, the NS is frequently compared to the posteromedial cortical nucleus of the amygdala in mammals. However, the structure of these two nuclei is very different: the NS displays concentric laminar organization and is considered to be an invagination of the pallium protruding into the ventricle (Ulinski and Peterson, 1981). The NS has been the subject of relatively few investigations. The efferent connections of the NS have been reported by several authors (Halpern and Silfen, 1974;Hoogland, 1977;Voneida and Sligar, 1979;Halpern, 1980;Stoll and Hoogland, 1984), while systematic analysis of its intrinsic organization has been more limited (Ulinski and Kanarek, 1973). Recently, the distribution of various chemicals in reptilian brains has been studied histochemically (Smeets et al. , 1986;Perez-Clausell, 1988;Smeets, 1988;Smeets and Steinbusch, 1988;. Further information on the structure of the NS is needed. The present study was undertaken to elucidate the intrinsic organization of the NS in the striated snake using the rapid Golgi method. The results revealed detailed features of neuronal morphology and terminal patterns of the afferent fibers, and these are discussed in the context of previous cytoarchitectural, hodologi...

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The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko

Cited by 63 publications

References 45 publications

Evolution of the basal ganglia: new perspectives through a comparative approach

Evolution of the basal ganglia: new perspectives through a comparative approach

Serotonergic modulation of male-like pseudocopulatory behavior in the parthenogenetic whiptail lizard, Cnemidophorus uniparens

A Golgi Study on the Nucleus Sphericus of the Striated Snake, Elaphe quadrivirgata

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