Melatonin is a ubiquitous hormone, produced both by vertebrates and invertebrates, including also... more Melatonin is a ubiquitous hormone, produced both by vertebrates and invertebrates, including also bacteria and protozoans, besides superior plants. Its main role is to regulate biological rhythms, thanks to a secretion pattern reflecting the daily light-dark cycle, determining so-called circadian rhythms. Over the year, this daily rhythm changes slightly but constantly with changing daylength, generating a circannual or seasonal rhythm. Circulating melatonin in mammals is synthesized by the pineal gland (or epiphysis cerebri), a neuroendocrine structure situated on the roof of the third ventricle, belonging to the diencephalon. This gland in cetaceans is apparently absent, though there are controversial reports in the literature, some reporting its presence. In some species yet, some authors found it in some individuals, whereas other studies on conspecifics did not detect it. This is the case also for the common bottlenose dolphin (Tursiops truncatus), the subject of this study. Th...
This study describes the expression of the voltage operated calcium channels (VOCCs) subunits α1A... more This study describes the expression of the voltage operated calcium channels (VOCCs) subunits α1A (typical of the P/Q family) and α1D (of the L family) in the bovine hypothalamus. The expression of both P/Q and L families has been characterized in the brain of adult mammals. However, their distribution and expression during foetal neuronal differentiation have not yet been determined. The expression profile of the α1A and α1D pore-forming subunits was investigated during four embryonic stages in bovine foetuses. Our data suggest that the expressions of α1A and α1D are correlated during development, with an increase only in males that peaks on the last period of gestation. Bovine male hypothalami showed significantly higher α1A and α1D expression values in comparison to female ones during the whole developmental period. In the females, the expression profiles of both genes were constant during all the developmental time. Immunohistochemical studies confirmed the presence of the α1A and α1D protein subunits in foetal hypothalamic neurones starting from the third foetal stage. Our data provide new information on the hypothalamic expression of α1A and α1D subunits during development in a mammal with a long gestation period and a large and convoluted brain.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
Melatonin is a ubiquitous hormone, produced both by vertebrates and invertebrates, including also... more Melatonin is a ubiquitous hormone, produced both by vertebrates and invertebrates, including also bacteria and protozoans, besides superior plants. Its main role is to regulate biological rhythms, thanks to a secretion pattern reflecting the daily light-dark cycle, determining so-called circadian rhythms. Over the year, this daily rhythm changes slightly but constantly with changing daylength, generating a circannual or seasonal rhythm. Circulating melatonin in mammals is synthesized by the pineal gland (or epiphysis cerebri), a neuroendocrine structure situated on the roof of the third ventricle, belonging to the diencephalon. This gland in cetaceans is apparently absent, though there are controversial reports in the literature, some reporting its presence. In some species yet, some authors found it in some individuals, whereas other studies on conspecifics did not detect it. This is the case also for the common bottlenose dolphin (Tursiops truncatus), the subject of this study. Th...
This study describes the expression of the voltage operated calcium channels (VOCCs) subunits α1A... more This study describes the expression of the voltage operated calcium channels (VOCCs) subunits α1A (typical of the P/Q family) and α1D (of the L family) in the bovine hypothalamus. The expression of both P/Q and L families has been characterized in the brain of adult mammals. However, their distribution and expression during foetal neuronal differentiation have not yet been determined. The expression profile of the α1A and α1D pore-forming subunits was investigated during four embryonic stages in bovine foetuses. Our data suggest that the expressions of α1A and α1D are correlated during development, with an increase only in males that peaks on the last period of gestation. Bovine male hypothalami showed significantly higher α1A and α1D expression values in comparison to female ones during the whole developmental period. In the females, the expression profiles of both genes were constant during all the developmental time. Immunohistochemical studies confirmed the presence of the α1A and α1D protein subunits in foetal hypothalamic neurones starting from the third foetal stage. Our data provide new information on the hypothalamic expression of α1A and α1D subunits during development in a mammal with a long gestation period and a large and convoluted brain.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that... more ABSTRACT The sperm whale (Physeter macrocephalus, Linnaeus 1758) possesses the largest brain that ever existed. Relatively few authors have dealt with it and the available descriptions are heterogeneous, with only few data about brain weight or gross anatomy. In fact the central nervous system of large cetaceans is quite difficult to obtain, given the huge body size and the low frequency of strandings of recently dead individuals. Furthermore, since the skull of the sperm whale underwent an extreme transformation for the accommodation of the spermaceti organ, the cranial cavity is surrounded by thick layers of bone and thus difficult to reach under field conditions. We recently had the chance to extract the brain from two stranded sperm whales whose bodies were in good condition. In the present note we describe the main macroscopic characteristics of the sperm whale brain, including its weight and Encephalization Quotient, review the available literature, and describe a possible new approach to the removal and preservation of the organ under field conditions.
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