Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies of endoepithelial-triggered reflexes, such as nasal respiratory reflexes, are difficult to carry out in humans without a non-traumatic and reliable stimulation device. The air puff stimulator described allows us to deliver air puffs of brief duration at various intensities, frequencies, and temperatures. The stimulation is non-traumatizing and non-nociceptive. We have successfully used it in animals as a source of specific stimuli to enable us to study central and peripheral neuronal responses evoked by activation of endonasal dynamically sensitive receptors. Immunohistochemical studies of the c-fos expression evoked during sneezing elicited by air puffs provided additional evidence for the specificity of this particular stimulation technique. We suggest that the use of such a non-traumatizing air puff stimulator could be extended to human studies. It might be particularly useful in developmental studies of endoepithelial-triggered reflexes such as those respiratory reflexes whose immaturity at birth can be life-threatening.
 ...
PMID:An improved mechanical air puff stimulator that allows activation of a variety of endoepithelial receptors and is suitable for the study of reflexes in animals and humans. 948 87

Juvenile rats can exhibit maternal behavior after being exposed continuously to rat pups, a process called sensitization. Maternal behavior in juveniles is robust and is similar to adult maternal behavior (Mayer and Rosenblatt [1979] Dev. Psychobiol. 12:407-424; Gray and Chesley [684] J. Comp. Psychol. 98:91-99). In this study, immunocytochemical detection of the protein products of two immediate-early genes, c-fos and fosB, was used as a tool to identify forebrain neuronal populations involved in the maternal behavior of 27-day-old juvenile rats compared with 60-day-old adults. To sensitize them, rats were exposed continuously to foster pups. Once they were maternal, they were isolated from pups overnight, reexposed to pups for 2 hours, and then killed. Nonmaternal control animals also were isolated overnight and were either reexposed to pups for 2 hours or kept isolated from pups before killing. The lateral habenula (LH) was the only area in which both maternal juveniles and maternal adults had more c-Fos-immunoreactive (-Ir) neurons compared with controls. In maternal adults, the number of neurons that expressed c-Fos and FosB immunoreactivity increased in the medial preoptic area (MPO) and the ventral bed nucleus of the stria terminalis (BSTv), whereas the dorsal bed nucleus of the stria terminalis (BSTd) and the medial and cortical nuclei of the amygdala (MEA and COA, respectively) had increases only in the number of neurons that expressed c-Fos immunoreactivity. In contrast, juveniles, whether or not they were maternal, had the same number of c-Fos-IR and FosB-Ir neurons in all these areas. The adult-like increase in the number of c-Fos-Ir neurons found in maternal juveniles suggests that the juvenile LH participates in the neural circuit that supports maternal behavior in an adult-like manner. The lack of c-fos or fosB induction in the MPO, BSTv, BSTd, COA, or MEA of maternal juveniles compared with maternal adults may reflect the immaturity of these brain regions in juvenile rats. Exactly what this immaturity consists of and when the responses of these regions become adult-like remain to be determined.
 ...
PMID:Induction of c-fos-like and fosB-like immunoreactivity reveals forebrain neuronal populations involved differentially in pup-mediated maternal behavior in juvenile and adult rats. 1057 2

In ovine and human pregnancy, fetal swallowing contributes importantly to amniotic fluid homeostasis. Fetal dipsogenic responsiveness to short-term plasma hyperosmolality develops in late gestation, although fetal swallowing is not stimulated in response to long-term plasma osmolality increases (2 to 3%), which typically stimulate adult drinking behavior. To explore the near-term fetal plasma osmolality threshold for swallowing stimulation, we examined the effects of i.v. hypertonic saline-induced subacute increases in plasma hypertonicity on fetal swallowing behavior. Central sites of activation were examined by c-fos expression in putative dipsogenic nuclei. The results demonstrate that subacute 2 to 3% plasma osmolality increases do not stimulate near-term ovine fetal swallowing. However, fetal swallowing activity significantly increased (3 times) after plasma osmolality increased >6% above basal values. Consistent with a specific dipsogenic response, i.v. hypertonic saline induced c-fos expression in the anterior third ventricle region, a putative dipsogenic center, as well as in the fetal hindbrain. The stimulation of fetal swallowing under conditions of higher osmotic stimulation and the correlation with forebrain c-fos expression indicates that near-term fetal osmoregulation mechanisms are functional, although not completely mature. Reduced fetal dipsogenic responsiveness may result from altered osmoreceptor sensitivity, downstream neuronal or synaptic immaturity, or potentially inhibitory actions of stimulated hindbrain nuclei.
 ...
PMID:Plasma osmolality dipsogenic thresholds and c-fos expression in the near-term ovine fetus. 1132 52

Although initiation of drug abuse occurs primarily during adolescence, little is known about the central effects of nicotine and other abused drugs during this developmental period. Here evidence, derived from studies in rodents, is presented that suggests that tobacco use initiation during early adolescence results from a higher reward value of nicotine. The developmental profiles of the rewarding effects of other abused drugs, such as cocaine, differ from that of nicotine. Using in situ hybridization to quantify mRNA levels of the immediate early gene, cfos, the neuronal activating effects of nicotine in limbic and sensory cortices at different developmental stages are evaluated. Significant age changes in basal levels of cfos mRNA expression in cortical regions are observed, with a peak of responding of limbic cortices during early adolescence. A changing pattern of nicotine-induced neuronal activation is seen across the developmental spectrum, with unique differences in both limbic and sensory cortex responding during adolescence. An attentional set-shifting task was also used to evaluate whether the observed differences during adolescence reflect early functional immaturity of prefrontal cortices that regulate motivated behavior and psychostimulant responding. The finding of significantly better responding during adolescence suggests apparent functional maturity of prefrontal circuits and greater cognitive flexibility at younger ages. These findings in rodent models suggest that adolescence is a period of altered sensitivity to environmental stimuli, including abused drugs. Further efforts are required to overcome technical challenges in order to evaluate drug effects systematically in this age group.
 ...
PMID:Adolescent development of forebrain stimulant responsiveness: insights from animal studies. 1525 85

This article intends to show how the cerebellum, a structure ordinarily not considered in mediating breathing or cardiovascular control, may play a critical role in compensatory responses particularly to hypoxic insults occurring pre and/or postnatally and thus may be involved in the sudden unexplained perinatal and infant death. Besides the ontogenesis of the cerebellar cortex in man, we reported alterations of biopathological features (neuronal immaturity, altered apoptotic programs, negative expression of somatostatin and EN2 gene, intense c-fos expression positivity, astrogliosis) in the cortex and in the dentate nucleus of the 63% of sudden deaths, and only in 10% of the controls. The correlation of these results with the mother's smoking habit was highly significant. Therefore, we support the hypothesis, already expressed in previous studies on brainstem, of a close relation between maternal cigarette smoking and a wide range of morpho-physiological defects of the brain, leading to unexplained sudden death in stillbirths, newborns, and Sudden Infant Death Syndrome (SIDS) victims.
 ...
PMID:Alterations of biological features of the cerebellum in sudden perinatal and infant death. 1690 Jun 66