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169 Schedule of the origin of the hypothalamic dopaminergic neurons in male and female rats
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167 SOME PECULIARITES OF ELABORATON REFLEXES DELAYED CONDITIONAL ASCENDING ROW OF MAMMALS.
ROLE OF HYPOTHALAMIC MONOAMINES IN DIFFERENTIATION OF THE TARGET PEPTIDERGIC NEURONS
OF IN
M. Ugrumo@ and A. Cala?. ’ Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia; a Institut des Neurosciences, CNRS URA 1488, Universite P. et M. Curie, Paris, France.
T.N.Sollertinskaja. Sechenov Institute of Evolutionary Physiology and Biochemistry, StPetersburg, Russia. In chronic experiments on insectivores (hedgehogs), rodents (rabbits) and primates (monkey, macaca rhesus) the peculiarities of elaboration delayed conditional reflexes were investigated.The experiments carried out using food model of Pavlov classicical method with simultaneous registration of vegetative and somatic components of condional reflexes. It was shown that in hedgehogs the elaboration of delayed condional reflexes (type of shortmemory) be required too many connections of conditional stimulus with unconditional ones to receive short - term (S-10 s) delayed conditional reflexes. In rodents (rabbits) the formation of delayed conditional reflexes is possible to elaborate conditional reflexes with delay about IS-25 s after swithching on the conditional stimulus and this kind of conditional reflexes is retained as long as several days. In monkeys the different type of the short- and longterm types of memory were possible to elaborate within of one or two experimental days with delay of conditional stimulus for several tenth of second. It is necessary to point out that after interruption in work with delayed condional reflexes they may be retained easily within 3 - 5 months. The experiments on monkeys was shown that administration of neuropeptide vasopressin accompanyied by facilitatory effect on long-term memory. These findings show that possibility to elaborate more prolonged of delayed conditional reflexes is increased with ascending row of mammals.
The differentiation of the hypothalamic peptidergic neurons (vasopressin, oxytocin, vasoactive intestinal polypcptide, somatostatin, gonadotropin-releasing hormone) has been studied in viva and in vitro under monoamine depletion in the rat brain either from the 12th embryonic day (E) till El5E20 or from the 2nd postnatal day (P) till PlO. Catecholamines and serotonin were depleted by daily systemic injections of amethyl-p-tyrosine and p-chlorophenylalanine. respectively. The monoamine deficiency stimulated in the differentiating target neurons: a) peptide gene expression; b) peptide synthesis; c) maturation of the mechanism of peptide release in response to membrane depolarization; d) the neuron migration to the places of the final settling. These effects are realized during certain periods of ontogenesis and sometimes last until adulthood. Some effects are characterized by sexual dimorphism. Thus, monoamines appear to inhibit the differentiation of their target peptidergic neurons during critical periods of prenatal and early postnatal life.
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170
SCHEDULE OF THE ORIGIN OF THE HYPOTHALAMIC DOPAMINERGIC NEURONS IN MALE AND FEMALE RATS
ROLE OF CATECHOLAMINES IN THE DEVELOPMENT OF THE HYPOTHALAMIC SOMATOSTATIN SYSTEM IN RAT FETUSES
1. Balan”, M. Ugrumo@. N. Bonsova”, A. Cala?, Ch. Pilgrim’, I. Reisert’ and J. Thibaul?. ‘Inst. of Developmental Biology, Russ. Acad. Sci., Moscow, Russia; b Instit. des Neurosciences, CNRS URA 1488, Universitt P. et M. Curie and dCollege de France, Paris, France; ’ Universitat Ulm, UIm, Germany.
A. Sapronova”, V. Melnikova’, M. Ugrumov”, A. Faivreb. C. Loudesb and C. Kordonb. ’ Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia; b INSERM U. 159, Centre Paul Broca, Paris, France. The development of the hypothalamic somatostatin (SS) system has been evaluated in rat fetuses following daily from the 11th embryonic day (E) to E20 injections to pregnant mothers of the inhibitor of the catecholamine (CA) synthesis, a-methyl-ptyrosine (aMPT), or saline in the control. According to radioimmunoassay. the CA depletion resulted in a significant increase of SS concentration at E21. In the second series, the pregnant rats were daily treated with aMPT from El 1 to El5 or El 7 that was followed by culturing of the hypothalamus for 12 days. After the CA depletion, the SS release is stimulated by an excess of potassium, if the hypothalamus is cultured from both El7 and E15. In the control, the membrane depolarization stimulated SS release only in the hypothalamus explanted in tissue culture at El7, thus, suggesting an inhibitory influence of CA on the differentiation of SS neurons.
This study has determined the birthdates of the tyrosine hydroxylase-(TH) immunoreactive (IR) neurons in the zona incerta @I), p&ventricular nucleus (PeVN) and arcuate nucleus (AN) of male and female rats. “Long-survival” [3H]thymidine autoradiography combined with TH immunocytochemistry, the first enzyme of the catecholamine synthesis, was used to solve this problem. In males, TH-IR neurons originate in the ZI from the 12th to the 13th embryonic day (E), while in the PeVN and AN this process is prolonged till E16. The maximal yield of TH IR neurons was achieved at El2 in the ZI, E12-El4 in the PeVN, and El5 in the AN. There was a sexual dimorphism in timing of the TH-IR neuron birthdates in all hypothalamic regions studied: a) the generation of the majority of TH-IR neurons in the ZI in males precedes that in females, b) the generation of TH-IR neurons in the AN of males is delayed compared to females, c) the general yield of TH-IR neurons in any studied hypothalamic region of females exceeds that in males. Sex differences mentioned above manifest themselves before E16, i.e. before the onset of sex differences in androgen levels and can. therefore, be considered as the consequence of a hormone-independent realization of genetic sex.
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167 SOME PECULIARITES OF ELABORATON REFLEXES DELAYED CONDITIONAL ASCENDING ROW OF MAMMALS.
ROLE OF HYPOTHALAMIC MONOAMINES IN DIFFERENTIATION OF THE TARGET PEPTIDERGIC NEURONS
OF IN
M. Ugrumo@ and A. Cala?. ’ Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia; a Institut des Neurosciences, CNRS URA 1488, Universite P. et M. Curie, Paris, France.
T.N.Sollertinskaja. Sechenov Institute of Evolutionary Physiology and Biochemistry, StPetersburg, Russia. In chronic experiments on insectivores (hedgehogs), rodents (rabbits) and primates (monkey, macaca rhesus) the peculiarities of elaboration delayed conditional reflexes were investigated.The experiments carried out using food model of Pavlov classicical method with simultaneous registration of vegetative and somatic components of condional reflexes. It was shown that in hedgehogs the elaboration of delayed condional reflexes (type of shortmemory) be required too many connections of conditional stimulus with unconditional ones to receive short - term (S-10 s) delayed conditional reflexes. In rodents (rabbits) the formation of delayed conditional reflexes is possible to elaborate conditional reflexes with delay about IS-25 s after swithching on the conditional stimulus and this kind of conditional reflexes is retained as long as several days. In monkeys the different type of the short- and longterm types of memory were possible to elaborate within of one or two experimental days with delay of conditional stimulus for several tenth of second. It is necessary to point out that after interruption in work with delayed condional reflexes they may be retained easily within 3 - 5 months. The experiments on monkeys was shown that administration of neuropeptide vasopressin accompanyied by facilitatory effect on long-term memory. These findings show that possibility to elaborate more prolonged of delayed conditional reflexes is increased with ascending row of mammals.
The differentiation of the hypothalamic peptidergic neurons (vasopressin, oxytocin, vasoactive intestinal polypcptide, somatostatin, gonadotropin-releasing hormone) has been studied in viva and in vitro under monoamine depletion in the rat brain either from the 12th embryonic day (E) till El5E20 or from the 2nd postnatal day (P) till PlO. Catecholamines and serotonin were depleted by daily systemic injections of amethyl-p-tyrosine and p-chlorophenylalanine. respectively. The monoamine deficiency stimulated in the differentiating target neurons: a) peptide gene expression; b) peptide synthesis; c) maturation of the mechanism of peptide release in response to membrane depolarization; d) the neuron migration to the places of the final settling. These effects are realized during certain periods of ontogenesis and sometimes last until adulthood. Some effects are characterized by sexual dimorphism. Thus, monoamines appear to inhibit the differentiation of their target peptidergic neurons during critical periods of prenatal and early postnatal life.
169
170
SCHEDULE OF THE ORIGIN OF THE HYPOTHALAMIC DOPAMINERGIC NEURONS IN MALE AND FEMALE RATS
ROLE OF CATECHOLAMINES IN THE DEVELOPMENT OF THE HYPOTHALAMIC SOMATOSTATIN SYSTEM IN RAT FETUSES
1. Balan”, M. Ugrumo@. N. Bonsova”, A. Cala?, Ch. Pilgrim’, I. Reisert’ and J. Thibaul?. ‘Inst. of Developmental Biology, Russ. Acad. Sci., Moscow, Russia; b Instit. des Neurosciences, CNRS URA 1488, Universitt P. et M. Curie and dCollege de France, Paris, France; ’ Universitat Ulm, UIm, Germany.
A. Sapronova”, V. Melnikova’, M. Ugrumov”, A. Faivreb. C. Loudesb and C. Kordonb. ’ Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia; b INSERM U. 159, Centre Paul Broca, Paris, France. The development of the hypothalamic somatostatin (SS) system has been evaluated in rat fetuses following daily from the 11th embryonic day (E) to E20 injections to pregnant mothers of the inhibitor of the catecholamine (CA) synthesis, a-methyl-ptyrosine (aMPT), or saline in the control. According to radioimmunoassay. the CA depletion resulted in a significant increase of SS concentration at E21. In the second series, the pregnant rats were daily treated with aMPT from El 1 to El5 or El 7 that was followed by culturing of the hypothalamus for 12 days. After the CA depletion, the SS release is stimulated by an excess of potassium, if the hypothalamus is cultured from both El7 and E15. In the control, the membrane depolarization stimulated SS release only in the hypothalamus explanted in tissue culture at El7, thus, suggesting an inhibitory influence of CA on the differentiation of SS neurons.
This study has determined the birthdates of the tyrosine hydroxylase-(TH) immunoreactive (IR) neurons in the zona incerta @I), p&ventricular nucleus (PeVN) and arcuate nucleus (AN) of male and female rats. “Long-survival” [3H]thymidine autoradiography combined with TH immunocytochemistry, the first enzyme of the catecholamine synthesis, was used to solve this problem. In males, TH-IR neurons originate in the ZI from the 12th to the 13th embryonic day (E), while in the PeVN and AN this process is prolonged till E16. The maximal yield of TH IR neurons was achieved at El2 in the ZI, E12-El4 in the PeVN, and El5 in the AN. There was a sexual dimorphism in timing of the TH-IR neuron birthdates in all hypothalamic regions studied: a) the generation of the majority of TH-IR neurons in the ZI in males precedes that in females, b) the generation of TH-IR neurons in the AN of males is delayed compared to females, c) the general yield of TH-IR neurons in any studied hypothalamic region of females exceeds that in males. Sex differences mentioned above manifest themselves before E16, i.e. before the onset of sex differences in androgen levels and can. therefore, be considered as the consequence of a hormone-independent realization of genetic sex.
91