Flower Pot Research Articles

Sleep Deprivation by the “Flower Pot” Technique and Spatial Reference Memory

Youngblood, B. D., J. Zhou, G. N. Smagin, D. H. Ryan and R. B. S. Harris. Sleep deprivation by the “flower pot” technique and spatial reference memory. Physiol Behav 61(2) 249–256, 1997.—This study investigated whether paradoxical, or rapid eye movement (REM), sleep deprivation (SD) affected spatial memory. SD was induced in male Wistar rats by housing them on small platforms over water. They fell into the water if they lost muscle tone. Controls were either housed in tanks with large platforms (TC) or in normal cages (CC). All rats had free access to food and water. Each day they were tested in a place-learning set task using a Morris water maze. The rats were released from 6 different starting points (sets) and allowed 2 min to find a submerged platform. Two trials were conducted from each starting point. SD caused a significant decrement in performance in Trial 1 from Day 2. By Day 4, when distance swum to find the platform was plotted against set, area under the curve was doubled in SD compared to that in TC and CC rats, indicating a significant impairment in reference spatial memory. There was no consistent effect on working memory, indicated by Trial 2. SD caused weight loss and increased serum corticosterone compared to that in CC rats. There were no differences in concentrations of hypothalamic, hippocampal, or cortical catecholamines or their metabolites. Serotonin metabolism was elevated in the hypothalamus and hippocampus in SD rats. These results indicate that SD induced in rats housed on small platforms causes a substantial impairment of reference memory. The memory deficit may not be specific to SD because the rats are physically stressed and lose some nonREM sleep when housed in these conditions.

Haustoria of Cuscuta japonica, a Holoparasitic Flowering Plant, Are Induced by the Cooperative Effects of Far-Red Light and Tactile Stimuli

When seedlings of Cuscuta japonica were grown with Vigna radiata (the host plant) in a flower pot for 6 d under white light and then irradiated with far-red or blue light (ca. 6 [ano photons m~2 s1), the seedlings parasitized V. radiata. However, no parasitism of the seedlings was observed under red or white light or in darkness. The parasitic behavior of seedlings of C. japonica was observed even if an acrylic rod was used as a substitute for the host plant. Upon incubation under far-red light, the seedling twined tightly around the rod and developed haustoria towards it. Haustoria also developed when apical and subapical regions of seedlings were held between two glass plates that were about 0.7 mm apart and were irradiated with far-red light. However, no haustoria were induced by either the hold or irradiation alone. These results indicate that parasitism of Cuscuta japonica is controlled by the cooperative effects of two physical signals, far-red light and appropriate tactile pressure. Our findings suggest that parasitism by the genus Cuscuta involves a novel strategy.

Changes in monoamines and their metabolite concentrations in REM sleep-deprived rat forebrain nuclei

Rapid eye movement sleep deprivation (REMSD) is a potent Stressor in rats. Behavioral abnormalities such. as passive and active avoidance, locomotor activity, problem solving, sensory information processing, and the development of adaptive copping strategy in response to repeated stress are among the earliest obvious symptoms of REMSD, the mechanism for which remain largely unknown. The aim of this study was to determine whether 96 h of REMSD causes changes in monoamine neurotransmitters concentrations in rat forebrain regions (frontal cortex, FC; parietal cortex, PC, and striatum) that are involved in mediating higher brain functions such as attentional mechanisms, sensory information processing, and locomotor activity, which are severely affected in REMSD conditions. Rats were subjected to 96 h of REMSD using inverted flower pot water tank technique. To account for the stress associated with water tanks, a tank control group (TC) was included where the animals could reside comfortably on a large pedestal in the water tank. Regional brain concentrations of norepinephrine (NE), dopamine (DA), dihydroxyphenyacetic acid (DOPAC), l-3,4-dihydroxyphenylalanine ( l-DOPA), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (HIAA) were determined by electrochemical detection using high-performance liquid chromatography. The concentrations of serotonin and its metabolite, HIAA, was reduced in the frontal and parietal cortexes of REMSD rats compared with TC or cage control (CC) group. NE, DA, DOPAC, and HVA concentrations in FC and PC of REMSD animals were remained unchanged compared with TC or CC rats. A significant increase in the concentrations of DA metabolites was observed in the striatum of REMSD rats when compared with CC and TC rats. There was a 29 and 31% increase in the concentration of striatal DA in REMSD group compared to the TC and CC groups, respectively; however, these percentages were not statistically different. Striatal NE, 5-HT, and HIAA concentrations were not significantly different among the three groups. These results suggest that 96 h of REMSD alters dopaminergic and serotonergic systems in different locations in rat brain. The effect of REMSD on the serotonergic systems are localized in the cerebral cortex, whereas dopaminergic metabolism is increased in the striatum.

Conchoid of Nicomedes from reflections and refractions in a cone

Reflections and refractions of a sheet of light from a truncated cone are shown to produce the ancient figure of the conchoid of Nicomedes when imaged on the basal plane. The idea can be easily demonstrated using a truncated cone (here a glazed flower pot is used) and a laser pointer. This result may be of interest in the area of nonimaging optics.

Effect of rapid eye movement sleep deprivation on 5′-nucleotidase activity in the rat brain

Adenosine has been implicated in the regulation of rapid eye movement sleep (REMS). In an attempt to understand the mechanism of production of adenosine in relation to REMS it was hypothesized that should it be involved in REMS, the latter's deprivation is likely to affect its synthetic machinery. Hence, male albino rats were deprived of REMS by the flower pot technique and the activity of 5′-nucleotidase, an enzyme responsible for adenosine synthesis, was estimated in the cerebrum, cerebellum and brain stem. Suitable control experiments were conducted to rule out the non-specific effects. The results showed that 5′-nucleotidase activity decreased only after 4 days deprivation and in the cerebrum only; while short-term (2 days) deprivation did not affect the enzyme activity in any of the brain areas. The altered enzyme activity returned to baseline level after recovery from REMS deprivation. The results from other control experiments suggested that the effects were primarily due to REMS deprivation and not due to non-specific factors. It is proposed that if adenosine is involved in REMS, its production is unlikely to depend on 5′-nucleotidase or it may account primarily for EEG desynchronization.

Rapid eye movement sleep deprivation decreases membrane fluidity in the rat brain

In this study we examined the effects of rapid eye movement sleep (REMS) deprivation on synaptosomal and microsomal membrane fluidity by studying 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence polarization in control as well as REMS-deprived rats. The flower pot technique was used to perform 24, 48 and 96 h REMS deprivation. Suitable control experiments were carried out to rule out the nonspecific effects. The results showed that DPH fluorescence polarization increased both in the microsome as well as in the synaptosome in REMS-deprived animals, except in the cerebellum, indicating that there was a generalized decrease in membrane fluidity in the rat brain. The alterations in membrane fluidity returned to baseline upon recovery from REMS deprivation. Control experiments suggested that the alterations were primarily caused by REMS deprivation and not due to nonspecific effects. This finding supports REMS deprivation induced other changes reported earlier. This increase in membrane rigidity could be at least one of the possibilities for REMS loss induced alterations in physiological phenomena including membrane bound enzyme activities and receptor densities.

Effect of chronic REM sleep deprivation on pituitary, hypothalamus and hippocampus PGE 2 and PGD 2 biosynthesis in the mouse

Given the often reported relationships between sleep-wake regulation and the cerebral prostaglandins (PGs), the effect of chronic rapid eye movement ( REM) sleep deprivation on brain PGE 2 and PGD 2 biosynthesis in mouse was evaluated, since they are known to have opposite actions as respectively wake- and sleep-inducing substances. Mice were subjected to 5 and 10 days of REM sleep deprivation by the flower pot technique. After sacrifice, PGE 2 and PGD 2 were determined in the pituitary, hypothalamus and hippocampus. Except in the pituitary where no changes were shown, the PGE 2 PGD 2 ratio was significantly enhanced after 5 and 10 days of REM sleep loss, when compared to control. These results showed an alteration of cerebral PGE 2 and PGD 2 biosynthesis, resulting in a shift from PGD 2 toward PGE 2. These results were not consistent with a role of PGD 2 as a sleep-promoting substance as, if that was the case, it would be increased during the REM sleep deprivation. But they do not rule out its involvement as a facilitating substance.

Rapid Eye Movement Sleep-Deprivation-Induced Changes in Glucose Metabolic Enzymes in Rat Brain

Glucose metabolism and energy expenditure are altered during rapid eye movement (REM) sleep. To understand this mechanism, it was hypothesized that the enzymes involved in the metabolism of glucose, viz. hexokinase and glucose-6-phosphatase, are affected by REM sleep deprivation. The flower pot technique was used for 1-, 2- and 4-day periods of REM sleep deprivation. Suitable control experiments were carried out to rule out the nonspecific effects. The results showed that glucose-6-phosphatase was first to be affected, and it showed decreased activity. In longer periods of deprivation, there was an increase in hexokinase activity. Both the altered enzyme activities returned to baseline level on recovery from REM sleep deprivation. Control experiments suggest that alterations were primarily caused by REM sleep deprivation, not nonspecific effects.

Rapid eye movement sleep deprivation increases chloride-sensitive Mg-ATPase activity in the rat brain

Rapid eye movement sleep deprivation is known to affect central neuronal excitability and responsiveness. Because chloride-sensitive Mg-ATPase is known to affect the neuronal transmembrane potential, this study was conducted to investigate if the enzyme activity might be affected on deprivation. The flower pot method was used for 2 and 4 days of deprivation and suitable control experiments were conducted. The enzyme activity was estimated in the microsomal preparation of the whole brain as well as in different areas of the brain in rats. The results suggested that the deprivation increased the enzyme activity although the chloride-insensitive Mg-ATPase activity remained unaffected. The increase in the enzyme activity is likelyto reduce the neuronal hyperpolarization. The findings fit in with existing knowledge and help in explaining earlier observations.

Habenula and thalamus cell transplants restore normal sleep behaviors disrupted by denervation of the interpeduncular nucleus

The preceding companion study (Eckenrode et al., 1992) showed that cell suspension transplants of fetal habenula cells placed near the interpeduncular nucleus (IPN) following lesions of the fasciculus retroflexus (FR) restore the normal pattern of substance P (SP) staining in habenular target subnuclei of the IPN in both perinatal and adult hosts, and restore ChAT staining in the IPN of perinatal hosts. Similarly placed transplants of fetal thalamus cells only restore ChAT staining in the IPN of adult hosts. In this study, we examined the functional significance of these restored staining patterns. We used a behavioral measure of the integrity of REM-stage and non-REM-stage sleep, the "flower pot" test, and assayed (1) normal adult rats, (2) FR-lesioned control animals (neonatal or adult operates), (3) animals receiving FR lesions and transplants of fetal habenula cells (perinatal or adult hosts), and (4) animals receiving FR lesions and transplants of fetal thalamus cells (adult hosts). FR lesions decrease markedly the muscle atonia component of REM sleep and reduce duration of sleep episodes. Transplants that restore SP staining in the IPN (habenular transplants into either perinatal or adult lesion hosts) restore normal frequency of REM atonia; transplants that restore ChAT staining (habenular transplants into perinatal hosts or thalamic transplants into adult hosts) restore normal duration of sleep episodes. The number of SP-immunoreactive cells in the transplants predicts recovery of REM atonia, and the number of ChAT cells in habenular (but not thalamic) transplants predicts restoration of sleep duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of REM sleep deprivation on molecular forms of acetylcholinesterase in rats

Since REM sleep deprivation was reported to increase the activity of acetylcholinesterase, an attempt was made to investigate whether the different forms of enzyme could be affected selectively. The flower pot method was used for deprivation and suitable control experiments were conducted. The bound and the soluble forms, if affected would show an increase or a decrease, respectively, on REM deprivation. The former is affected first in the pons while the latter in the medulla. The findings support the pontomedullary cholinergic mechanism for the generation of REM sleep. Though there may be a possibility of conversion of the free to the bound form, the increase in the latter was more than the decrease in the former.

Linkage between Epilithic Algal Growth and Water Column Nutrients in Softwater Lakes

We examined the dependence of epilithic algal standing crop, production, and nutrient limitation upon water column nutrients in 12 softwater lakes of northeastern Pennsylvania. Elevated dissolved inorganic nitrogen accompanied low dissolved inorganic carbon in the more acidic lakes, while P varied little within the study area. The growth of epilithon on clay flower pot substrata diffusing combinations of N (NaNO3), P (Na2HPO4), and C (NaHCO3) was compared with growth on control substrata to evaluate which of the three nutrients limited growth in each lake. Standing crop accrual as chlorophyll a on control substrata averaged 0.8 μg/cm2, with little variation among lakes. Nutrient limitation of growth, however, was strongly related to lake alkalinity. Chlorophyll a was typically enhanced by N and/or P only in lakes with alkalinity greater than ~100 μeq/L and responded strongly to C enrichment in the two most acidic lakes. Combined addition of all three nutrients produced the largest chlorophyll a accrual in all 12 lakes. Invertebrate grazer biomass, dominated by chironomids in the more acidic lakes and by snails at higher alkalinity, was negatively related to chlorophyll a on these NPC substrata (r = −0.57, p = 0.05) and may have reduced algal standing crop well below nutrient-sustainable levels in some lakes.

Stirring the Biology Teaching Pot with Discrepant Events

THE biology class was in the process of finishing up a genetics laboratory exercise. Students had planted and germinated corn seeds that exhibited two phenotypes-one with chlorophyll and the other without chlorophyll (albino). The teacher, hoping to move on to a discussion of seeds, asked the students how the albino plants were able to grow even though they possessed no chlorophyll. During the ensuing silence of thought, Frank's hand shot up and without being called upon, he said, My uncle is an agronomist, and he told me that when corn is planted in the dark it grows faster than in light. Could that be true? Mary, who had until then been staring out of the window, turned around and commented that Frank's uncle was crazy and did not know what he was talking about. This was not the hoped for response; however, the teacher knew that Frank's uncle was correct, and that this would serve as a place to begin the discussion. The teacher had two options at this point: explain the reason or encourage an open-ended discussion by saying, I know that it doesn't seem possible, but if you consider all the facts, you might agree with the answer given by Frank's uncle. The teacher wisely chose the second option. For the next 20 minutes, the teacher focused student discussion on the details of plant growth, then asked students what stimulated plants to grow. Water, food, sunlight and minerals were all mentioned as sources. The teacher, in probing these responses, asked specifically which were essential for corn seeds to grow in the dark. The students were not sure and requested additional information about plant growth; they had a desire to know. The students, by themselves, still could not resolve the problem. Even with their insistence for closure, the teacher decided to perpetuate the activity. The students were then guided to design an experiment to test the hypothesis that corn seedlings grow faster in the dark. With as little input as possible from the teacher, the students were given corn seeds and asked to proceed with their experiment. Once they thought they had a good design with sufficient controls for relevant variables, the students assembled the necessary equipment to plant the seeds in two flower pots labeled A and B. Flower pot A was kept in a lighted area and flower pot B was placed in darkness. Twice daily they observed and measured the seeds' rate of growth (any combination of time chosen was acceptable) until several days past the successful germination of all the viable seeds. (It was then observationally concluded by the students that the corn seeds in flower pot B had grown taller than the ones in A.) The event that took place in this hypothetical biology classroom is a good example of how one might motivate interest and provoke active student participation. This would then challenge their basic conceptual framework of events in the world around them. When the student predictably admits, It can't happen that way; that just isn't so, the teacher has created an opportunity for discovery through logical inquiry and/or application of scientific concepts and principles. This is a teaching maneuver adopted to elicit appropriate student behaviors that promote the achievement of desired educational objectives. Indeed,

Short-term REM sleep deprivation increases acetylcholinesterase activity in the medulla of rats

Involvement of cholinergic ponto-medullary brainstem mechanism regulating rapid eye movement (REM) sleep is known. Recently it was found that though short term REM deprivation influenced brainstem neuronal excitability, the activity of the brainstem acetylcholinesterase was not affected until after 96 h deprivation. Therefore, it was hypothesized that short-term REM deprivation might influence acetylcholinesterase in a restricted brainstem region. Results of this study show that the enzyme activity increased only in the medulla after 24 and 48 h REM deprivation. The flower pot technique was used for depriving the experimental rats of REM sleep. Suitable control experiments were conducted to rule out the possibility of non-specific effects. Thus, the medullary cholinergic mechanism probably is more important for REM.

Effect of REM sleep deprivation on rat brain acetylcholinesterase

Acetylcholinesterase activity was compared in control, rapid eye movement sleep-deprived and recovered rat brain. The activity was estimated in the whole brain, cerebrum, brain stem and cerebellum. Flower pot technique was used for continuing deprivation for two, four and eight days. The results showed that the enzyme activity increased signficantly in the deprived rat brain and it returned to control/normal level on recovery. The enzyme activity increased first in the brain stem, while the activity in the cerebellum showed no significant change. Control experiments suggest that the increase was primarily caused by the deprivation. The finding fits well with existing knowledge and would possibly help in explaining earlier observations.

Establishment of a successive culture of an obligatory parasitic flowering plant, Cuscuta japonica, in vitro

A culture system of an obligatory parasitic flowering plant, Cuscuta japonica, was established for studying parasitic behavior and floral evocation. The culture system consists of culturing excised stems of aseptic Cuscuta seedlings on a modified Murashige and Skoog medium containing 1 mg · 1 −1 of kinetin and 10% coconut water (K-medium). When the excised stem was incubated horizontally on the K-medium under continuous light conditions, novel protuberances developed from cut ends of the stem, and subsequently lateral buds elongated into lateral shoots. The lateral shoots with the novel proturberances grew rapidly and resembled the parasitizing plants in the field. These lateral shoots were propagated by successively culturing the stems excised from newly elongated lateral shoots, and the subcultured lateral shoots occasionally projected a few haustorium-like organs. The lateral shoots cultured in vitro could parasitize in vivo on the stem of host plants grown in a flower pot, and after that the parasitizing plants bloomed and developed seeds. Moreover, when the subcultured lateral shoots were cultured under short day conditions, floral buds developed on the elongated lateral shoot. The anthesis and seed development progressed in this in vitro culture.

Effects of liming on nutrient limitation of epilithic algae in an acid lake

The processes of lake acidification and lake restoration frequently involve major changes in DIC and DIN, both of which may potentially limit algal growth. We evaluate nutrient limitation of benthic algal biomass and species abundances during summers 1987 and 1989, before and after the liming of Lake Earnest (NE Pennsylvania) in November 1988. Limestone addition caused immediate increases in pH from 4.7 to 7.2. Alkalinity was −34 μeq L−1 in summer 1987, but rose to 620 μeq L−1 in summer 1989, whereas DIN declined from 10.7 μmol L−1 to 1.1 μmol L−1 The algae were sampled after 45 to 46 d from clay flower pot substrates diffusing combinations of N, P and C. Algal biomass was strongly C-limited in 1987, but NP-limited in 1989. Mougeotia sp., which comprised >99% of total algal biovolume prior to liming, declined to < 1% of the community on control substrates, while Oedogonium sp. increased to 43% of total biovolume in 1989. The stimulation of chlorophyll-a accrual with C-enrichment during 1987 was consistent with the later increase in chlorophyll-a on control substrates following liming. Species enhanced by the diffused nutrients, however, generally differed from those which dominated the natural community.

… OF SHERDS AND SOIL AND SEALING LAYERS, OF COBBLING AND COINS…

Summary. From 1985 to 1987 an experiment was conducted alongside an excavation to examine the effect of trampling on cobbled layers, and to see if the movement of small objects could change their stratigraphic relationships. An experimental area was excavated and backfilled with soil and a cobbled layer containing plastic markers, flower pot sherds and coins. The area, part of a path, was subjected to daily trampling, and was excavated after seventeen months, using normal excavation methods; all the soil was dry sieved. The results show varying recovery rates and horizontal movements for different types of object, and demonstrate the need for further investigation of the causes and implications of differential movement of buried objects.

Effects of nutrient (N, P, C) enrichment, grazing and depth upon littoral periphyton of a softwater lake

Three field experiments were performed in Lake Lacawac, PA to determine the importance of potentially limiting nutrients relative to other factors (grazing, depth) in structuring shallow water algal periphyton communities. All three experiments measured periphyton growth (as chlorophyll-a, AFDM or biovolumes of the algal taxa) on artificial clay flower pot substrates which released specified nutrients to their outer surfaces.

Sleep deprivation increases susceptibility to kindled and penicillin seizure events during all waking and sleep states in cats.

The timing of amygdala kindled and penicillin seizures was studied throughout the sleep-wake cycle in eight cats following near total sleep deprivation and a control procedure that did not affect sleep time. Sleep loss was induced by 24-h exposure to a modified "flower pot" procedure employing a small pedestal. The control procedure consisted of 24-h exposure to a larger pedestal. Sleep loss increased susceptibility to generalized kindled and penicillin seizures during all waking and sleep states but did not alter temporal patterns of seizure susceptibility. Both before and after sleep loss, kindled cats showed maximal seizure susceptibility, indexed by lowest seizure thresholds, during slow wave sleep (SWS) and transitions from SWS to REM sleep (REMS). The spike-wave discharges and motor seizures of systemic penicillin epilepsy were always most frequent during SWS and during drowsiness after awakening. Both models were invariably most resistant to seizures during stable REMS. To explain sleep- and sleep loss-activated seizures, we summarized previous work suggesting that sleep abnormalities dictate the timing of seizures and are exacerbated by sleep loss. Abnormal behavioral arousals and pathological somatomotor system excitability occur in both models and are particularly pronounced during seizure-prone intervals. Sleep loss may magnify somatomotor system hyperexcitability patterns in all states, thus allowing abnormal motor arousals and seizures to intrude during seizure-prone and seizure-resistant sleep and waking states.