Immunochemical localization of platelet-derived growth factor in placenta and its possible role in pre-eclampsia.

BACKGROUND: Platelet-derived growth factor (PDGF) has an important role in cellular function, proliferation, and angiogenesis. It is also associated with tissue injury and repair, and its involvement in atherosclerosis has been studied extensively. Tissue injury is also found in pre-eclampsia (PRE). The morphological and physiological changes that are taking place in the PRE placenta may be associated with this growth factor. The objective of this study was to determine if PDGF-AA and its alpha receptor are present in the cells and vessels of normotensive (NORM) and PRE placentas at term. METHODS: Placental tissue was obtained from 6 preeclamptic and 8 normotensive women. Gestational age ranged from 38-42 weeks. Deliveries were either vaginal (vag, n = 10) or c-section (c-sec, n = 4). Tissue samples were analyzed for PDGF-AA by immunocytochemistry. RESULTS: PDGF-AA and the alpha receptor were present in both NORM and PRE placentas. Immunoreactive staining revealed PDGF-AA and its receptor in the intimal/endothelial layer of fetal vessels and the trophoblastic layer. Staining intensity was greater in preeclamptic tissue when obliterative endarteritis was present. CONCLUSIONS: In pre-eclampsia, PDGF-AA may play a role in the restructuring of the fetoplacental vasculature, in particular when there is inflammation of the vascular intimal layer, as found in obliterative endarteritis. Increased staining in the trophoblast layer in patients with obliterative endarteritis also may be indicative of more widespread damage throughout the placenta itself, and PDGF-AA may play a significant role in the repair of this damage.

Glutamate containing neurons in the cat superior colliculus revealed by immunocytochemistry.

Glutamate is the probable neurotransmitter of both retinal and cortical afferents to the cat superior colliculus (SC). The present study shows that glutamate is also contained in many postsynaptic neurons in SC. The distribution, morphology, and ultrastructure of neurons in SC were examined using glutamate antibody immunocytochemistry. Labeled cells were widely distributed throughout, but a specific laminar pattern was evident. Relatively few cells were found in the zonal and upper superficial gray layers (SGL). A dense band of intensely labeled neurons was found within the deep superficial gray and upper optic layers. Many cells were also labeled in the deeper layers. Labeled cells had varied sizes and morphologies. Soma diameters ranged from 9-67 microns, with a mean of 22 microns. Cells with stellate, vertical fusiform, and multipolar morphologies were labeled. Cells in the deep subdivision all had morphologies and sizes typical of projection neurons. To determine if labeled cells in the dense band were also projection neurons, WGA-HRP was injected into the lateral posterior nucleus and these sections were double-labeled with the glutamate antibody. Over one-half of cells in the dense band that were labeled by HRP were also obviously labeled by antibody. At the electron-microscope level, both medium- and large-sized neurons were also labeled by glutamate antibodies. These cells had different but characteristic morphologies.

Effects of dopamine and fluphenazine on field potential amplitude in the salamander olfactory bulb.

The effects of dopamine (DA) and fluphenazine (FLU), a phenothiazine DA receptor antagonist, were examined in the salamander olfactory bulb. Field potentials were recorded in the granule cell layer of superfused hemibrain preparations, and the amplitude of the large positive peak was compared following stimulation of the olfactory nerve (ON) and lateral olfactory tract (OT). In preparations superfused with normal amphibian Ringer's solution, the large peak occurred 14-21 ms after either ON or OT stimulation. It therefore appeared to reflect the activation of granule cell synapses with mitral cells, as in olfactory bulbs of other species. In three groups of preparations that were superfused with single concentrations of DA, significant decreases were observed in the amplitude of the large peak of ON- and OT-evoked potentials with increases in concentration from 5-200 microM. Moreover, with 5 microM DA and 50 microM DA, significant decreases were observed in the amplitude of the large peak of ON-evoked potentials with increases in superfusion time from 1-15 min. With each DA concentration tested, the mean percentage decrease in the ON-evoked potentials was significantly larger than the mean percentage decrease in the OT-evoked potentials. In five groups of preparations that were superfused with single concentrations of FLU, significant decreases were also observed in the amplitude of the large peak of ON- and OT-evoked potentials with increases in concentration from 0.5-150 microM. With 100 microM FLU and 150 microM FLU, significant decreases were observed in the amplitude of the large peak of both ON- and OT-evoked potentials with increases in superfusion time from 5-10 min. With each FLU concentration tested, the mean percentage change in the ON-evoked potentials was significantly larger than the mean percentage change in the OT-evoked potentials. The stronger effects of DA and FLU on the ON-evoked than OT-evoked potentials suggested that both drugs target receptors in the rostral (superficial) layers of the salamander olfactory bulb which have a higher density or affinity for DA and FLU than receptors in the more caudal (deep) layers of the bulb. When preparations were superfused with an equimolar mixture of DA and FLU at the ED50 concentrations (50 microM for both), FLU blocked approximately 50% of the decrease in the amplitude of the ON-evoked potentials relative to the decrease measured in preparations superfused with DA alone. Since FLU depressed the amplitude of ON-evoked potentials when it was tested alone, however, the rostral DA receptors could occur on both the olfactory receptor cell axons and their postsynaptic targets, or FLU could limit mitral/tufted cell excitation by affecting other types of receptors or voltage-sensitive Ca2+ channels. Results of this study which show that DA and FLU reduce the amplitude of evoked potentials in the salamander olfactory bulb provide evidence for the occurrence of DA receptors in the amphibian brain. More importantly, the stronger effects of DA and FLU on the ON-evoked than OT-evoked potentials suggest that the DA receptors could function to limit the excitation of cells at an early synaptic level in the salamander bulb. By modulating spatiotemporal patterns of synaptic activity in the glomerular layer, the receptors could profoundly influence the initial encoding of information about odors.

Long- and short-term monocular deprivation in the rhesus monkey: effects on visual fields and optokinetic nystagmus.

Monkeys with 1 eyelid sutured within 2 weeks of birth for 7 or 14 d (short-term monocular deprivation, n = 5) or for 18-26 months (long-term monocular deprivation, n = 5) were tested for visual and oculomotor function at approximately 2 years of age. Long-term monocularly deprived animals were behaviorally blind when visual inputs were restricted to the deprived eye. There was no sparing of the monocular segment of the visual field, and optokinetic nystagmus could not be elicited even with vertical stripes up to 15 degrees in width. These behavioral deficits could not be accounted for by optical or retinal abnormalities. In contrast, short-term monocularly deprived animals displayed normal visual fields and optokinetic nystagmus was driven by both eyes. Slow-phase gain was reduced and directional asymmetries were observed when optokinetic stimulation was restricted to the deprived eye.