摘要:

The distribution of vasotocin in the brains of the turtle Pseudemys scripta elegans and the snake Python regius was studied with immunohistochemical methods. In both species, vasotocin-immunoreactive (VTi) cells were found in the supraoptic nucleus, the paraventricular nucleus and the bed nucleus of the stria terminalis. No VTi cell bodies were seen in the brainstem. Vasotocinergic fibers were found in all major brain divisions. Intrahypothalamic VTi fibers were observed between the supraoptic and the paraventricular nuclei and in the median eminence? An extensive network of extrahypothalamic VTi fibers extends from the olfactory bulb to the spinal cord. Limbic structures, such as the nucleus accumbens, the septal area and the ventral amygdaloid nucQsus, contain a moderate to dense VTi plexus. Other areas with a substantial number of VTi fibers are the lateral habenular nucleus, the ventral tegmental area, the substantia nigra, the locus coeruleus and the nucleus of the solrmxy tract. Sex-related differences in the density of the VTi fibers were observed in the lateral septal nucleus, the midbrain periaqueductal gray and, to a lesser extent, in the ventral amygdaloid nucleus, the lateral habenular nucleus, the ventral tegmental area and the substantia nigra. In these areas, the density of VTi fibers is higher in males than in females. The distribution of vasotocin-like immunoreactivity in the brains of Pseudemys and Python resembles the pattern previously observed in the lizard Gekko gecko. However, among the three species several differences exist, the most remarkable one being the variation in number of liquor-contacting VTi cells in the paraventricular nucleus.

ISSN:0006-8977    

DOI:10.1159/000115857

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

The distribution of vasotocin in the brains of the turtle Pseudemys scripta elegans and the snake Python regius was studied with immunohistochemical methods. In both species, vasotocin-immunoreactive (VTi) cells were found in the supraoptic nucleus, the paraventricular nucleus and the bed nucleus of the stria terminalis. No VTi cell bodies were seen in the brainstem. Vasotocinergic fibers were found in all major brain divisions. Intrahypothalamic VTi fibers were observed between the supraoptic and the paraventricular nuclei and in the median eminence? An extensive network of extrahypothalamic VTi fibers extends from the olfactory bulb to the spinal cord. Limbic structures, such as the nucleus accumbens, the septal area and the ventral amygdaloid nucQsus, contain a moderate to dense VTi plexus. Other areas with a substantial number of VTi fibers are the lateral habenular nucleus, the ventral tegmental area, the substantia nigra, the locus coeruleus and the nucleus of the solrmxy tract. Sex-related differences in the density of the VTi fibers were observed in the lateral septal nucleus, the midbrain periaqueductal gray and, to a lesser extent, in the ventral amygdaloid nucleus, the lateral habenular nucleus, the ventral tegmental area and the substantia nigra. In these areas, the density of VTi fibers is higher in males than in females. The distribution of vasotocin-like immunoreactivity in the brains of Pseudemys and Python resembles the pattern previously observed in the lizard Gekko gecko. However, among the three species several differences exist, the most remarkable one being the variation in number of liquor-contacting VTi cells in the paraventricular nucleus.

ISSN:0006-8977    

DOI:10.1159/000316070

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Estimates of visual acuity in a pelagic freshwater zooplanktivorous fish, the white crappie (Pomoxis annularis, Centrarchidae), were made using a behavioral measure, the maximum observed prey pursuit distance (MxPD), and a histological measure, the density of cone cells in the retina. The greatest number of pursuits occurs in the 0–30° wedge of the visual field; 87% of all pursuits occur in the first 40°. The longest pursuits (200 mm) also occur in this area and generally get shorter from 0 to 180° (from forward-directed) in the visual field. Consistent with the behavioral results, the largest number of cone photoreceptors (13,000/mm2) is found in the far temporal retina along the eye's horizontal meridian. Cone cell densities in the corresponding region of the nasal retina are approximately half this value. The number of cones decreases dorsally and ventrally from the horizontal meridian. Although the absolute values of visual acuity calculated from cone cell topography (i.e. MxPDs of 500 mm) are 2–3 times greater than those observed behaviorally (i.e. MxPDs of 200 mm), the trends in visual acuity across the visual field obtained from both measures are consistent. We suggest that overestimates of visual acuity obtained from cone cell counts alone result from this measure's not accounting for, among other properties of the nervous system, cone cell convergence onto ganglion cells and higher brain centers. Behavioral measures of visual acuity are, therefore, likely to yield a more accurate estimate of an animal's visual abilities.

ISSN:0006-8977    

DOI:10.1159/000115858

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Catecholamine concentrations (pg/ml) in the cerebrospinal fluid (CSF) of prepubertal (n = 9) and adult (n = 18) horses were determined by radioenzymatic assay. Norepinephrine was low or non detectable in all CSF samples. In contrast, measurable CSF dopamine concentrations were effected by age, reproductive status and exogenous steroid treatments. The concentration of dopamine in the CSF of prepubertal females (733 ± 92) was greater (p < 0.05) than the concentration in the CSF of prepubertal males (117 ± 67). Prepubertal male horses which were treated with testosterone for 5 days (50 mg/day) had elevated (p < 0.05) dopamine concentrations (2,533 ± 1,160) in the CSF compared to control males. In adult mares, dopamine was lower (p < 0.05) in the ovulatory season (25 ± 10) than during the anovulatory season (200 ± 101). Daily intramuscular estradiol-17β (5 mg/day) injections had no effect (p < 0.05) on dopamine concentrations in the CSF of seasonally anovulatory mares (250 ± 35). Further, concentrations of dopamine in the CSF of long-term ovariectomized mares (80 ± 21) were not influenced (p < .05) by season. These results suggest that age, sex and gonadal steroids may effect dopamine, but not norepinephrine, concentrations in the brain ventricular system of the equine species. Further, seasonal effects on CSF dopamine concentrations are dependent upon the presence of the ovaries.

ISSN:0006-8977    

DOI:10.1159/000115859

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

All known brachyceran flies have inherited the same trapezoidal pattern of rhabdomeres in the ommatidia of the compound eye, different from that of their presumed nematoceran ancestors. The projection pattern of axons to lamina cartridges needs to match this in order to generate efficient neural superposition vision. This pattern has been traced in serial sections or via stimulated dye uptake in two families that diverged from the dipteran stem line more than 200 million years ago (Rhagionidae, Stratiomyidae) and in one family of intermediate age (Dolichopodidae). All show the same asymmetric projection as modern muscoid families and a concordantly 180°-twisted axon bundle, suggesting that evolution to the 'modern' versions of both optics and projection coincided closely in evolutionary time. The basic developmental plan of the cartridge has also been retained since the origin of the Brachycera, but the synaptic participation of at least one axon (that of photoreceptor R7) varies markedly between species.

ISSN:0006-8977    

DOI:10.1159/000115860

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

All known brachyceran flies have inherited the same trapezoidal pattern of rhabdomeres in the ommatidia of the compound eye, different from that of their presumed nematoceran ancestors. The projection pattern of axons to lamina cartridges needs to match this in order to generate efficient neural superposition vision. This pattern has been traced in serial sections or via stimulated dye uptake in two families that diverged from the dipteran stem line more than 200 million years ago (Rhagionidae, Stratiomyidae) and in one family of intermediate age (Dolichopodidae). All show the same asymmetric projection as modern muscoid families and a concordantly 180°-twisted axon bundle, suggesting that evolution to the 'modern' versions of both optics and projection coincided closely in evolutionary time. The basic developmental plan of the cartridge has also been retained since the origin of the Brachycera, but the synaptic participation of at least one axon (that of photoreceptor R7) varies markedly between species.

ISSN:0006-8977    

DOI:10.1159/000316071

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0006-8977    

DOI:10.1159/000115861

出版商:S. Karger AG    

年代:1990

数据来源: Karger