Neuropeptides in Rat Brain Development

Boer, G.J.; Swaab, Dick F.; Uylings, H.B.M.; Boer, Kees; Buijs, Ruud M.; Velis, Demetrios N.

doi:10.1016/s0079-6123(08)60066-7

Cited by 44 publications

(8 citation statements)

References 60 publications

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“…In addition, an early electrical activity may also be relevant for the maturation of other structures by increasing axonal peptide release. The peptides are released before birth and increasing evidence suggests that they exert developmental functions on both central and peripheral structures (Boer et al ., 1980a; Carter et al ., 1993). For instance, a transient OT or AVP receptor expression is observed in brain and kidney during development (Schmidt et al ., 1990; Tribollet et al ., 1991a), and Brattleboro rats display several developmental deficiencies such as decreased brain weight and increased noradrenaline brain content (Boer et al ., 1995).…”

Section: Discussionmentioning

confidence: 99%

Correlation between electrophysiological and morphological characteristics during maturation of rat supraoptic neurons

Chevaleyre

Moos

Desarménien

2001

Eur J of Neuroscience

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The neurohypophysial peptides oxytocin (OT) and vasopressin (AVP) are well known for their role in reproductive functions and fluid balance regulation, respectively. During development, these peptides are thought to act as trophic factors on both peripheral and central structures. However, despite this early developmental function, the maturation of their secreting neurons remains poorly investigated. In this study, we have characterized the electrical and morphological characteristics displayed by OT and AVP supraoptic (SO) neurons between embryonic day 21 and postnatal day 20. Transient changes in passive membrane properties, correlated with a transient increase in the dendritic arborization, were observed at the beginning of the second postnatal week (PW2). The action potential matured mostly during PW1 and its threshold progressively hyperpolarized in parallel with the resting membrane potential. During PW1, SO neurons displayed unique characteristics with a low-threshold Ca(2+)-dependent depolarizing potential and a prominent hyperpolarization-activated current (I(h) ). This latter is involved in a depolarizing sag during hyperpolarization and an after hyperpolarizing potential following a depolarization. During this period, maintaining E(Cl) unchanged by the use of gramicidin-perforated patch recordings revealed excitatory GABAergic potentials, that became inhibitory during PW2, whilst glutamatergic potential appeared. The electrical activity was very erratic in young neurons and progressively differentiated in the typical firing observed in mature neurons (tonic and phasic for OT and AVP neurons, respectively) during PW2--3. These results show that the development of electrical properties of SO neurons is correlated with the maturation of their dendritic arborization.

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Section: Discussionmentioning

confidence: 99%

Correlation between electrophysiological and morphological characteristics during maturation of rat supraoptic neurons

Chevaleyre

Moos

Desarménien

2001

Eur J of Neuroscience

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“…However, postnatal brains were further dissected to remove the hypothalamus and median eminence, which were homogenized together for analysis. Over 99% of the AVP and OT in the rat CNS is found in these dissected brain areas postnatally (Boer et al, 1980~;Caste1 et al, 1984;Sofroniew, 1985;Boer, 1987).…”

Section: Methodsmentioning

confidence: 99%

Differential biosynthesis and posttranslational processing of vasopressin and oxytocin in rat brain during embryonic and postnatal development

Altstein

Gainer

1988

J. Neurosci.

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The biosynthesis and posttranslational processing of arginine vasopressin (AVP) and oxytocin (OT) peptides in the developing rat brain and pituitary were studied using antibodies and complementary separation methods that permitted a quantitative radioimmunoassay (RIA) analysis of precursor, intermediate, and completely processed forms of the peptides. Precursor forms of the peptides were first detected in rat brain as early as embryonic day (E) 15 for AVP and E17 for OT. Proteolytic cleavage products of the precursors were detected 1 d later for both peptides. AVP was present in a fully processed (amidated) from immediately (E16) and throughout fetal development. OT was cleaved from its precursor starting on E18 but remained in an intermediate (C-terminal extended) form until E21, when amidated OT was first detected in the pituitary. Hence, Pro-AVP processing in the fetus was immediate and complete, whereas Pro-OT processing in the fetus was much slower and incomplete, resulting in the generation of partially processed, nonamidated stable forms of the peptide (OT-Gly10, OT-Gly10-Lys11, and OT-Gly10-Lys11-Arg12). The presence of OT-Gly10-Lys11-Arg12 as a major, stable intermediate form, indicated that the in vivo pattern of endoproteolytic cleavage occurred principally at the C-terminus of the pair of basic amino acids at the tripeptide spacer sequence (Gly-Lys-Arg) in the precursor. Although both precursors were first expressed nearly simultaneously in the brain, the steady-state levels of the precursors were very different throughout fetal life. From E16-E21, the quantities of AVP precursors and peptides were 5- to 10-fold greater than those of OT, suggesting a much higher level of precursor biosynthesis in the AVP neurons. In addition to these differences in the regulation of biosynthesis and processing, AVP peptides were axonally transported to the pituitary 3 d earlier than OT peptides, and in far greater (20-fold) abundance. The early presence and abundance of amidated AVP in the brain and pituitary suggests a trophic function for this peptide during development.

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“…NGF promotes neurite outgrowth, neuronal survival, and other physiological changes in the peripheral sympathetic and sensory neurons and a number of neuron-like clonal cell lines (Levi-Montalcini and Angeletti, 1968;Greene, 1977;Schubert et al, 1978;Reynolds and Perez-Polo, 1981). Various neuropeptides have been proposed by many authors (Boer et al, 1980(Boer et al, , 1988Handelmann, 1985;Zagon and McLaughlin, 1987;Strand et al, 1989) as the substances having influence on neuronal proliferation, migration, differentiation, and organization of neuronal functional pathways. It has been shown that hippocampal formation has a n effect that accelerates neurite extension from chick parasympathetic or sympathetic neurons in vitro (Crutcher and Collins, 1982) and that a n addition of the hypothalamoneurohypophyseal complex (HNC) of the 45-day-old fetal guinea pig dramatically stimulates the synthesis of vasopressin and neurophysin in adult HNC incubated in an organ culture system (Pearson et al, 1975).…”

Section: Encephalectomized Fetuses (Group 2)mentioning

confidence: 99%

“…With this much productivity, we can say that the MBH is a treasury of neuroactive substances. Among the peptides derived from the MBH, proopiomelanocortin, ACTH and a-melanocyte-stimulating hormone were shown to have a moderate effect on the development of central and peripheral nervous system (Boer et al, 1980;Strand et al, 1989). It is thus quite possible that the developing MBH that has been either transplanted or cultured synthesizes some factors to promote neurogenesis of the LHRH neurons.…”

Section: Encephalectomized Fetuses (Group 2)mentioning

confidence: 99%

Further evidence of the presence of rat embryonic hypothalamic factors that induce the differentiation of gonadotrophic hormone‐releasing hormone‐containing secretory neurons

et al. 1991

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We examined the presence of factor(s) in the embryonic medial basal hypothalamus (MBH) that may influence nasal placode (NAP)-derived luteinizing hormone-releasing hormone (LHRH) neurons in determining their secretory phenotype. In this study, we performed organotypic culture and transplantation of the NAP from 12.5-day-old embryos of rats and vomeronasal organ (VNO) from 14.5-day-old embryos. Surgical operations, however, were performed on 16.5-day-old embryos. The NAP and VNO were cultured singly or with the MBH obtained from the embryos of the same age and, further, in a medium with a nerve growth factor or fibroblast growth factors. Although LHRH neurons were derived from the NAP and VNO in all the cultures, judging from numbers and cellular morphologies, the MBH was most effective. The VNO was transplanted into the third ventricle of adult female rats singly or with the cerebral cortex, the mesencephalon-myelencephalon complex, or the MBH from 14.5-day-old embryos. All the grafts gave rise to LHRH neurons, but the number of the neurons was far greater in the grafts cotransplanted with the MBH, in which the neurons projected long processes to blood capillaries and formed neurovascular complexes, the feature of which may suggest the occurrence of the secretory activity in the fibers. The animals were examined 5 days after the surgical operations. In rhinoectomized embryos, LHRH neurons were distributed throughout the brain in the same pattern as found in intact rats, showing normal cellular morphology. In the encephalectomized rats, immunoreactive LHRH cells were present only in the terminal ganglia. These findings indicate that the embryonal MBH has a factor (s) that is essential to the development of secretory LHRH neurons.

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Neuropeptides in Rat Brain Development

Cited by 44 publications

References 60 publications

Correlation between electrophysiological and morphological characteristics during maturation of rat supraoptic neurons

Correlation between electrophysiological and morphological characteristics during maturation of rat supraoptic neurons

Differential biosynthesis and posttranslational processing of vasopressin and oxytocin in rat brain during embryonic and postnatal development

Further evidence of the presence of rat embryonic hypothalamic factors that induce the differentiation of gonadotrophic hormone‐releasing hormone‐containing secretory neurons

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