Beta (CC)-chemokines as modulators of sleep: implications for HIV-induced alterations in arousal state.

Sleep is altered early in the course of HIV infection, before the onset of AIDS, indicating effects of the virus on neural processes. Previous observations suggest HIV envelope glycoproteins are possible mediators of these responses. Because some beta (CC)-chemokine receptors serve as co-receptors for HIV and bind HIV envelope glycoproteins, we determined in this study whether selected CC chemokine ligands alter sleep and whether their mRNAs are detectable in brain regions important for sleep. CCL4/MIP-1beta, but not CCL5/RANTES, injected centrally into rats prior to dark onset increased non-rapid eye movements sleep, fragmented sleep, and induced fever. mRNA for the chemokine receptor CCR3 was detectable under basal conditions in multiple brain regions. These data suggest some CC chemokines may also be involved in processes by which HIV alters sleep.

Development of a sexually dimorphic projection from the bed nuclei of the stria terminalis to the anteroventral periventricular nucleus in the rat.

The principal nucleus of the bed nuclei of the stria terminalis (BSTp) is larger in male rats and conveys olfactory information relevant for reproduction to the hypothalamus. In males, the BSTp provides a massive projection to the anteroventral periventricular nucleus of the preoptic region (AVPV), which in contrast to most sexually dimorphic nuclei contains more neurons in female rats. Injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin into the BSTp of adult female rats failed to demonstrate the strong projection to the AVPV observed previously in males. The ontogeny of this robust sex difference was examined by using the axonal marker DiI. The projection from the BSTp to the AVPV is established between postnatal day 9 (P9) and P10 in male rats and seems to be maintained during the juvenile period. Although labeled fibers extended from the BSTp toward the preoptic region in both male and female neonates, a similar connection with the AVPV was not apparent in female rats at any of the ages studied, and the density of labeled axons in the AVPV of P10 males was 20-fold greater than that of P10 females. A projection from the BSTp to the medial preoptic nucleus was also weaker in females but was much more substantial than that to the AVPV. These findings suggest that a sex- and region-specific activity influences the development of the projection from the BSTp to the AVPV, producing a sexually dimorphic architecture in pathways that convey olfactory information to the hypothalamus.

Suppression of p140trkA does not abolish nerve growth factor-mediated rescue of serum-free PC12 cells.

Programmed cell death, the intrinsic form of apoptosis, plays an integral role in those neurodegenerative events associated with age-related neuropathology. Neurotrophins (NTs), such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and NT-3, are required for survival of certain neurons, and thus their clinical use to counteract age- and pathology-associated neurodegeneration has been suggested, although mechanistic descriptions for NT cell rescue from apoptosis are not definitive. Here we attempted to isolate the individual actions of high-affinity tyrosine kinase (Trk) receptors and p75NGFR, the common low-affinity NT receptor, in NT rescue of apoptotic PC12 cells. Our results showed that whereas inhibiting Trk receptor phosphorylation abolishes NGF rescue of serum-deprived PC12 cells from apoptosis, TrkA suppression with antisense oligonucleotides did not. Also, although BDNF did not rescue naive serumless PC12 cells, which lack the BDNF-specific TrkB receptor, it significantly increased survival of TrkA-suppressed serum-starved PC12 cells. These data confirm the hypothesis that binding of any NT to Trk-free p75NGFR-bearing cells blocks apoptosis but also suggest that if Trk receptors are expressed, prohibiting Trk phosphorylation also blocks NT-mediated rescue from apoptosis.

Role of the cholinergic system in the regulation of neurotrophin synthesis.

Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) are members of the family of neurotrophins that are highly expressed in the adult hippocampus, and to a lesser extent, in the cerebral cortex and olfactory bulb. Since neuronal expression of neutrophins is controlled by some neurotransmitters and there is a topographical correlation between neurotrophin expression and cholinergic terminal distribution from the cholinergic basal forebrain (CBF) neurons in these areas, the question arises as to whether the cholinergic system can also regulate neurotrophin gene expression in the CNS. When CBF neurons were selectively and completely destroyed by intraventricular injection of 192 IgG-saporin, resulting in a cholinergic deafferentation of the hippocampus, cortex, and olfactory bulb, there were no significant changes in NGF, BDNF and/or NT-3 mRNA levels in these areas from 1 week to 5 months after the lesion. These results suggest that afferents from CBF neurons may not play a significant role in maintaining basal levels of neurotrophin gene expression in the adult rat brain under physiological conditions. However, potential cholinergic regulation of brain neurontrophin expression may occur under other circumstances.

In vitro glial responses to nerve growth factor.

Nerve growth factor (NGF) stimulates expression of the low affinity neurotrophin receptor p75NGFR mRNA in primary cultures of neonatal rat cortical type I astrocytes. Nerve growth factor treatment altered glial morphology in glial fibrillary acidic protein positive (GFAP+) cell cultures derived from newborn (P0) and 3-day-old (P3) rat pups. When P0- or P3-derived primary glial cultures were serum-deprived, in the presence of 200 pM NGF for 5 days, the flat polygonal glia present in culture assumed a fibrous morphology, an effect not seen in the untreated serum-deprived controls. The NGF effect on astrocytic morphology was blocked by continuous serum treatment. Nerve growth factor did not stimulate astrocytic proliferation under these culture conditions, as assayed by cell cycle analysis using 3H thymidine autoradiography. P0-derived primary glial cultures expressed the signal transducing neurotrophin receptors p145trkB and p140trkA as determined by reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR products were identified by sequencing or restriction enzyme analysis. Astrocytes internalized 125I-NGF at 37 degrees C but not at 4 degrees C, consistent with energy requirements for internalization. Also, internalization of 125I-NGF was abolished by the addition of a 300-1,000-fold excess of unlabeled NGF. Thus, astroglial cells in culture internalize NGF through a specific receptor-mediated process, express trkA and full-length trkB mRNAs at low levels, and respond to exogenous NGF by expressing a fibrous morphology under serum-free culture conditions.

Expression of p75NGFR TrkA, and TrkB mRNA in rat C6 glioma and type I astrocyte cultures.

Using a quantitative reverse transcription-polymerase chain reaction (RT-PCR) we have investigated the expression of the neurotrophin receptors p75NGFR, trkA, and trkB mRNAs in cultures of rat pup type I astrocytes and in the C6 rat glioma cell line. All three neurotrophin receptor mRNAs are expressed in both C6 cells and in type I astrocytic cultures. p75NGFR mRNA levels are increased by either cycloheximide or nerve growth factor (NGF) treatment of C6 cells as measured using RT-PCR. Type I astrocyte cultures also expressed p75NGFR mRNA and NGF treatment increased p75NGFR mRNA levels in these cultures. TrkB mRNA levels were increased by cycloheximide treatment of type I astrocyte cultures but not by NGF treatment. Using RT-PCR, trkA mRNA was detected in astrocytic cultures as well as in the rat C6 and PC-12 cell lines. We conclude that cultures of type I astrocytes express active NGF receptors and that glia can elicit a response to NGF as seen by an increase in p75NGFR mRNA levels following exposure to NGF.

Simultaneous transplant nephrectomy and ipsilateral second graft retransplantation.

Six cases of simultaneous transplant nephrectomy and retransplantation in the ipsilateral iliac fossa are presented. All primary grafts were lost due to chronic rejection. Patients were followed from forty-one to one hundred months after the second graft transplant. The sources for all grafts were either living related donors or cadavers. Graft nephrectomy was performed through the previous lower quadrant incision; the arterial and venous stumps of the primary grafts were used when possible. In all cases continuity of the urinary tract was reestablished with a Politano-Leadbetter ureteroneocystostomy. There appears to be no increased morbidity in any of these 6 cases, and the survival rate of the second graft is comparable to that of transplantation into the contralateral virginal fossa. Advantages of the simultaneous procedure are discussed.