摘要:

The distribution of dopamine (DA) immunoreactivy in the forebrain and midbrain of the red-eared turtle, Pseudemys scripta elegans, was studied using recently developed antibodies against DA. DA-containing cells were found around the glomeruli of the olfactory bulb but not in the telencephalon proper. In the diencephalon DA cells were observed in the preoptic region, several parts of the periventricular hypothalamic nucleus, the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus. In the midbrain DA cells were found in the ventral tegmental area, the substantia nigra and the presumed reptilian homologue of the mammalian A8 cell group. Dopaminergic fibers and terminals were observed throughout the whole brain, particularly in the telencephalon and diencephalon. The olfactory tubercle, the striatum and the nucleus accumbens appear to have the most dense innervation, but the anterior olfactory nucleus and the septal area also show numerous DA fibers and terminals. Cortical areas are in general not densely innervated by DA fibers. Compared to the results obtained for a lizard, Gekko gecko, with the same antibodies, the results of the present study are very similar as regards the distribution of DA neurons, fibers and terminals. In having better developed DA cell groups in the midbrain and a stronger innervation of the striatum, Pseudemys resembles mammals more than does Gekko. In contrast, the many cerebrospinal fluid-contacting DA neurons in the hypothalamus of Pseudemys are a primitive feature of the diencephalon. The previous immunohistochemical study of Gekko, a lizard, and the present account of Pseudemys, a turtle, indicate that at least two different lines of evolution exist within the reptiles with regard to the DA innervation of the dorsal ventricular ridge. One, including turtles and, probably, crocodilians with a weak DA innervation; and another, represented by lizards, with a strong DA immunoreactivity.

ISSN:0006-8977    

DOI:10.1159/000118642

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The distribution of dopamine (DA) immunoreactivy in the forebrain and midbrain of the red-eared turtle, Pseudemys scripta elegans, was studied using recently developed antibodies against DA. DA-containing cells were found around the glomeruli of the olfactory bulb but not in the telencephalon proper. In the diencephalon DA cells were observed in the preoptic region, several parts of the periventricular hypothalamic nucleus, the periventricular organ, the ependymal wall of the infundibular recess, the lateral hypothalamic area and the pretectal posterodorsal nucleus. In the midbrain DA cells were found in the ventral tegmental area, the substantia nigra and the presumed reptilian homologue of the mammalian A8 cell group. Dopaminergic fibers and terminals were observed throughout the whole brain, particularly in the telencephalon and diencephalon. The olfactory tubercle, the striatum and the nucleus accumbens appear to have the most dense innervation, but the anterior olfactory nucleus and the septal area also show numerous DA fibers and terminals. Cortical areas are in general not densely innervated by DA fibers. Compared to the results obtained for a lizard, Gekko gecko, with the same antibodies, the results of the present study are very similar as regards the distribution of DA neurons, fibers and terminals. In having better developed DA cell groups in the midbrain and a stronger innervation of the striatum, Pseudemys resembles mammals more than does Gekko. In contrast, the many cerebrospinal fluid-contacting DA neurons in the hypothalamus of Pseudemys are a primitive feature of the diencephalon. The previous immunohistochemical study of Gekko, a lizard, and the present account of Pseudemys, a turtle, indicate that at least two different lines of evolution exist within the reptiles with regard to the DA innervation of the dorsal ventricular ridge. One, including turtles and, probably, crocodilians with a weak DA innervation; and another, represented by lizards, with a strong DA immunoreactivity.

ISSN:0006-8977    

DOI:10.1159/000316023

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Although the optic tectum of nonmammalian vertebrates has been extensively studied anatomically, there is little information about the identification of neurotransmitters and the enzymes critical to their synthesis. Choline acetyltransferase (ChAT), the enzyme responsible for acetylcholine synthesis is presently regarded as the most reliable marker for cholinergic neurons, and its localization within putative cholinergic neurons has been made possible by the development of antibodies specific to ChAT. We have compared the immunocytochemical localization of ChAT to the histochemical staining of acetylcholinesterase (AChE) in the goldfish optic tectum. Goldfish brains reacted with the monoclonal antibody AB8 to ChAT have revealed that: (1) type XIV neurons are the only ChAT-positive cells in the tectum, and there are approximately 15,000 such cells per tectal hemisphere; (2) these neurons and other ChAT-containing afferent fibers form bands of label which correspond to those seen after AChE staining, and (3) many AChE-stained neurons do not contain ChAT. The immunohistochemical localization of ChAT has provided a direct method for determining the localization and organization of putative cholinergic structures in the optic tectum of goldfish. Future studies may elucidate the relationship of these cholinergic systems to the retinotectal projections, as there is close correspondence between AChE and ChAT location and the retinotectal termination patterns.

ISSN:0006-8977    

DOI:10.1159/000118643

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Four ecologically distinctive Neotropical bat species of the family Phyllostomidae were collected and their retinae surveyed immunohistochemically for the presence of neurotransmitter candidates: glucagon, somatostatin, vasoactive intestinal peptide, substance P (SP), methionine enkephalin, serotonin (5-HT) and two enzymes, glutamic acid decarboxylase (GAD) and tyrosine hydroxylase (TOH). In all four species immunoreactivity (IR) to GAD, TOH and SP was found. GAD-IR and SP-IR showed little interspecies variation whereas TOH-IR differed interspecifically in a pattern that matched the systematic relationships and the ecological characteristics of the bats. 5-HT-IR, which has not previously been reported from mammalian retinae, was found in fibers in the inner nuclear layer and in the outer and inner plexiform layers of Macrotus waterhousii, which is a relatively underived insectivorous phyllostomid bat, but was not found in the retinae from frugivorous or nectarivorous species.

ISSN:0006-8977    

DOI:10.1159/000118644

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Thalamo-telencephalic auditory pathways in the budgerigar (Melopsittacus undulatus) were studied using horseradish peroxidase (HRP) histochemistry and amino acids autoradiography. The results indicate that in this species the thalamic auditory relay nucleus, n. ovoidalis, projects upon a circumscribed region of the caudal and caudomedial neostriatum including field 'L' and immediately adjacent portions of the neostriatum intermedium, pars dorsolateral (NIDL). This region of NIDL also receives inputs from another thalamic nucleus, n. dorsolateralis posterior (DLP). In budgerigars, the DLP is in receipt of tectal inputs. Projections of DLP upon NIDL were confirmed with amino acids autoradiography. The results of the HRP experiments indicate that different portions of n. ovoidalis project upon different portions of field 'L' and NIDL. Neurons in the dorsal and lateral portions of the n. ovoidalis project upon more medial portions of field 'L'. Neurons located centrally in the n. ovoidalis project upon central and lateral portions of field 'L'. Neurons in the ventromedial portion of the n. ovoidalis are labeled in all cases in which HRP is placed in either field 'L' or in the DLP projection field immediately adjacent to field 'L' proper. HRP injections placed in NIDL lateral to the projection fields of the n. ovoidalis and DLP label neurons within other diencephalic nuclei including the n. subrotundus. The caudal and intermediate levels of the neostriatum intermedium apparently serve as a complex processing area for many thalamic inputs in this species. The existence of multiple ascending thalamo-telencephalic projections from portions of the thalamus receiving inputs from both the visual (i.e., tectal) and auditory (i.e., n. mesencephalicus lateralis pars dorsalis) portions of the midbrain roof (i.e., from DLP and from n. ovoidalis) suggests the possibility that intermodal associations may take place in these telencephalic fields. Such partially converging pathways may provide a basics for intermodal associations which are important in individual recognition and social signalling systems in this species.

ISSN:0006-8977    

DOI:10.1159/000118645

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Thalamo-telencephalic auditory pathways in the budgerigar (Melopsittacus undulatus) were studied using horseradish peroxidase (HRP) histochemistry and amino acids autoradiography. The results indicate that in this species the thalamic auditory relay nucleus, n. ovoidalis, projects upon a circumscribed region of the caudal and caudomedial neostriatum including field 'L' and immediately adjacent portions of the neostriatum intermedium, pars dorsolateral (NIDL). This region of NIDL also receives inputs from another thalamic nucleus, n. dorsolateralis posterior (DLP). In budgerigars, the DLP is in receipt of tectal inputs. Projections of DLP upon NIDL were confirmed with amino acids autoradiography. The results of the HRP experiments indicate that different portions of n. ovoidalis project upon different portions of field 'L' and NIDL. Neurons in the dorsal and lateral portions of the n. ovoidalis project upon more medial portions of field 'L'. Neurons located centrally in the n. ovoidalis project upon central and lateral portions of field 'L'. Neurons in the ventromedial portion of the n. ovoidalis are labeled in all cases in which HRP is placed in either field 'L' or in the DLP projection field immediately adjacent to field 'L' proper. HRP injections placed in NIDL lateral to the projection fields of the n. ovoidalis and DLP label neurons within other diencephalic nuclei including the n. subrotundus. The caudal and intermediate levels of the neostriatum intermedium apparently serve as a complex processing area for many thalamic inputs in this species. The existence of multiple ascending thalamo-telencephalic projections from portions of the thalamus receiving inputs from both the visual (i.e., tectal) and auditory (i.e., n. mesencephalicus lateralis pars dorsalis) portions of the midbrain roof (i.e., from DLP and from n. ovoidalis) suggests the possibility that intermodal associations may take place in these telencephalic fields. Such partially converging pathways may provide a basics for intermodal associations which are important in individual recognition and social signalling systems in this species.

ISSN:0006-8977    

DOI:10.1159/000316024

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

It is a general belief that the vestibulocollic reflex (VCR) is suppressed when subjects make voluntary head movements, although clear evidence is still lacking. Experiments were performed to examine whether the short-latency VCR evoked by electrical stimulation of the labyrinth is suppressed during active head turns in alert cats that were trained to make rapid horizontal head turns between the two milk feeders positioned 30° left and right in front of the cats. They were also trained to hold the head near the midline to wait for milk, and the VCRs recorded from splenius muscles in these behavioral situations were compared. The short-latency VCR remained during active head turns, and its amplitude was not consistently modulated by the direction of head turns, indicating that it was not suppressed by active head turns.

ISSN:0006-8977    

DOI:10.1159/000118646

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Scanning electron microscopy and standard histological techniques were used to describe the basic anatomy and postembryonic growth of the lateral line system of Cottus bairdi. The gross anatomy and distribution of lateral line neuromasts in canals and superficially on the skin are similar to what has been reported for many primitive actinopterygian fishes. Both canal and superficial neuromasts showed postembryonic growth in the number of hair cells and size of neuromasts, but canal neuromasts grew more elongate whereas superficial neuromast grew symmetrically. Neuromasts in the mandibular canal grew significantly faster than any other neuromasts and superficial neuromasts on the head showed the least amount of growth. Differential growth of the sculpin lateral line system may be related to the feeding behavior of the animal and to differences in the ambient levels of water noise to which larval and adult fish are exposed.

ISSN:0006-8977    

DOI:10.1159/000118647

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Scanning electron microscopy and standard histological techniques were used to describe the basic anatomy and postembryonic growth of the lateral line system of Cottus bairdi. The gross anatomy and distribution of lateral line neuromasts in canals and superficially on the skin are similar to what has been reported for many primitive actinopterygian fishes. Both canal and superficial neuromasts showed postembryonic growth in the number of hair cells and size of neuromasts, but canal neuromasts grew more elongate whereas superficial neuromast grew symmetrically. Neuromasts in the mandibular canal grew significantly faster than any other neuromasts and superficial neuromasts on the head showed the least amount of growth. Differential growth of the sculpin lateral line system may be related to the feeding behavior of the animal and to differences in the ambient levels of water noise to which larval and adult fish are exposed.

ISSN:0006-8977    

DOI:10.1159/000316025

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Growth characteristics of the total brain and of several individual brain regions are described in Apteronotus leptorhynchus. The increase of brain volume relative to total length growth results in a sigmoid growth curve, in which three phases – proportional growth, positive-allometric and negative-allometric growth – could be distinguished. This type of enlargement of the total brain is due to the differential volume increase of individual brain regions and to the increase in the volume of the rhombencephalic structures in particular. Pros- and mesencephalic regions mainly grow in accordance with the overall enlargement of the total brain throughout development, whereas rhombencephalic and certain nuclear structures show such isometric growth only with the onset of the juvenile period. The results are interpreted in the view of functionality of the individual brain regions.

ISSN:0006-8977    

DOI:10.1159/000118648

出版商:S. Karger AG    

年代:1987

数据来源: Karger