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Biomedical subjects

F C Barone

Publications and source records attributed to F C Barone.

136 records · Page 8Linked to original sources
PubMed1975

Effects of essential amino acids on central neurons.

Effects of eleven essential amino acids ejected by means of electrophoresis through five barrel glass microelectrodes on the frequency of extracellularly recorded action potentials of brain cells were determined. Data were collected on 129 cells from four different parts of the brains of 22 female hooded rats anesthetized with a mixture of chloralose and urethan. Eleven cells were tested in the cerebral cortex, 57 in the thalamus, 33 in the zona incerta, and 28 in the lateral hypothalamus. Of the eleven amino acids tested, cells of the zona incerta and lateral hypothalamus appear to be the most responsive and increases in discharge frequency were observed for all the amino acids except lysine and cystine. Cystine seems to be unusual in that it is the only amino acid tested which produces a decrease in the spontaneous discharge frequency. Cells of the cerebral cortex were not considered responsive in terms of the criteria of this study and displayed relatively high thresholds to all the essential amino acids. These results indicate some differential sensitivity of certain cells of the brain to essential amino acids which might be related to the centrally mediated anorexia which develops when rats are fed disproportionate amounts of these same amino acids in the diet.

Amino Acids↗
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Concomitant cortical expression of TNF-alpha and IL-1 beta mRNAs follows early response gene expression in transient focal ischemia.

The expression of tumor necrosis factor alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) mRNAs was significantly increased in the rat ischemic cortex following temporary occlusion of the middle cerebral artery (TMCAO) with reperfusion. Northern blot analysis demonstrated that the induction of TNF-alpha and IL-1 beta mRNAs occurred as early as 1 h after reperfusion, exhibiting a 4.6-fold increase (p < 0.05, n = 4) and 6.8-fold increase (p < 0.05, n = 4) in the ischemic cortex over control, respectively. TNF-alpha mRNA reached its peak at 3 h (8.0-fold, p < 0.05), whereas IL-1 beta mRNA reached its peak at 6 h (29.5-fold, p < 0.05). Both cytokine mRNA levels remained elevated for up to 2 d after reperfusion. In contrast to the time course of these cytokine mRNAs, c-fos and zif268 mRNAs, two early response genes, displayed a greater and earlier time-response profile. The early induction of c-fos and zif268 mRNAs in temporary brain ischemia with reperfusion suggests their roles in transcriptional regulation. The later concomitant expression of TNF-alpha and IL-1 beta suggests that these cytokines play an important role in the inflammatory response associated with focal ischemia.

Animals↗
PubMedDate not supplied

Effects of intragastric water infusion and gastric distension on hypothalamic neuronal activity.

The effects of gastric water infusion and distension were examined in neurons from various parts of the rat brain. Neurons in the lateral preoptic-lateral hypothalamic-medial forebrain bundle (LPA-LH-MFB) neuropil were sensitive to gastric water infusion and distension. Cells randomly selected and examined in other brain areas were less sensitive to the same stimulation which indicated that the effects were relatively specific. The results, in terms of changes in neuronal discharge frequency from an established baseline, indicate that many cells in the lateral preoptic-lateral hypothalamic-medical forebrain bundle area are affected by intragastric water infusion and gastric distension within a time period during which changes in drinking would normally occur. These neurons were also affected differentially by acute water deprivation. LPA-LH-MFB neurons in 24 hr water deprived animals were significantly more sensitive to water infusions and less sensitive to stomach distension when compared to cells recorded in animals maintained on ad lib eating and drinking. Some of these same neurons were also sensitive to changes in the extracellular concentrations of sodium and glucose. The results are discussed in terms of the involvement of the lateral preoptic-lateral hypothalamic-medial forebrain bundle neuropil in ingestive behavior.

Animals↗
PubMedDate not supplied

Effects of microiontophoretically applied chemicals on hypothalamic neural activity.

Seven barrel electrodes were utilized to record simultaneously from and apply chemicals to single neurons in the hypothalamus of anesthesized male hooded rats. When a stable baseline discharge frequency was established for lateral preoptic area (LPA) or lateral hypothalamic (LH) neurons, glutamate, norepinephrine, acetylcholine, glucose and sodium were administered microiontophoretically. In addition, the effects of microiontophoretically administered chemicals and LPA or LH electrical stimulation on hypothalamic neural activity were in some cases determined for the same neuron. Recordings from 53 hypothalamic neurons indicate that the direct application of these chemicals affect LPA and LH neural activity at relatively low ejection currents in a dose related manner. In the LPA, glutamate which has a nonspecific effect and increased the discharge frequency in 96% of the cells tested, was used to establish the reliability of the techniques and baseline. Norepinephrine decreased (73%), acetylcholine increased (28%) and decreased (12%), glucose increased (12%), and sodium increased (4%) discharge frequency. In the LH, glutamate increased (91%), norepinephrine decreased (33%), acetylcholine increased (50%) and decreased (14%), glucose increased (12%) and decreased (6%), and sodium increased (20%) discharge frequency. Also, significant relations between chemical and electrical stimulation suggest that norepinephrine and possibly acetylcholine might be involved in the interactions between the LPA and LH neurons. Results are discussed in terms of the neurochemical modulation of ingestive behavior.

Acetylcholine↗
PubMedDate not supplied

Effects of cervical vagus nerve stimulation on hypothalamic neuronal activity.

The effects of cervical vagus nerve stimulation on the activity of 56 neurons recorded in various parts of the rat brain were determined. Recordings were made from neurons in both the ipsilateral and contralateral hemispheres during vagus nerve stimulation. Both frequency, 10 to 100 Hz, and voltage, 1 to 20 V, of 0.5 msec pulses were applied to the nerve in a random manner over a 4 sec period while monitoring ongoing single neuronal activity. Frequency response relationships were established for 64% of the lateral preoptic-lateral hypothalamic-medial forebrain bundle (LPA-LH-MFB) neurons which were tested. Four types of LPA-LH-MFB neuronal responses were observed. Twenty percent of the neurons increased in discharge frequency as stimulation frequency was increased, 9% increased in discharge frequency as stimulation frequency was decreased, 23% decreased in discharge frequency as stimulation frequency was increased, and 14% decreased in discharge frequency as stimulation frequency was decreased. Increasing the stimulation voltage always enhanced the magnitude of the effects observed due to changing the stimulation frequency. Neurons observed in some other parts of the brain were not affected by the same stimulation. In addition, cells tested in the LPA-LH-MFB area which were previously tested and affected by gastric distension were also affected similarly by vagus nerve stimulation. Results are discussed in terms of peripheral afferent control over LPA-LH-MFB neuronal activity related to ingestive behavior.

Afferent Pathways↗
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A bipolar electrode for peripheral nerve stimulation.

The construction of a bipolar electrode for the stimulation of peripheral nerves is described. The electrode was designed for acute stimued in which the effects of peripheral nerve stimulation on central neural activity in rats were determined. Since the electrode can be secured into a fixed position, neural recordings can be made during the stimulation of various visceral nerves and the electrode can be easily adapted for chronic behavioral studies.

Animals↗
PubMedDate not supplied

The role of cytokines in the neuropathology of stroke and neurotrauma.

Accumulating evidence during the last decade has shown that the CNS can mount a well-defined inflammatory reaction to a variety of insults including trauma, ischemia, transplantation, viral infections as well as neurodegeneration. Many aspects of this centrally derived inflammatory response parallel to some extent the nature of such a reaction in the periphery. Through the recent application of molecular genetic techniques including PCR, utilization of cDNA probes in conjuncture with the availability of highly specific antibodies, new concepts are rapidly emerging as to the molecular mechanisms associated with the development of brain injury. In particular, the importance of cytokines, especially TNFalpha and IL-1beta, is emphasized in the propagation and maintenance of a CNS inflammatory response. This review summarizes evidence in support of a case for ischemia and trauma eliciting an inflammatory condition in the injured brain. The inflammatory condition consists of cells (neutrophils early after the onset of brain injury and subsequently monocyte infiltration) and mediators (cytokines, chemokines and adhesion molecules). It is clear that de novo up-regulation of pro-inflammatory cytokines, chemokines and endothelial-leukocyte adhesion molecules in the brain occurs soon following focal ischemia and trauma and at a time when the tissue injury is evolving. The significance of the inflammatory response and its contribution to brain injury are now becoming better understood. Evidence has emerged in support of the role of cytokines in driving the inflammatory response and that this process is causally related to the degree of brain injury. Evidence reviewed includes: (1) the capacity of specific cytokines to exacerbate brain damage; (2) the capacity of specific cytokine blockade to reduce ischemic brain damage; (3) depletion of circulating neutrophils reduces ischemic brain injury, and (4) antagonists of the endothelial-leukocyte adhesion interactions (e.g. anti-ICAM-1) reduce ischemic brain injury. Targeting the cytokines that drive the brain inflammatory response to injury provides opportunities to intervene with novel therapeutics in stroke and neurotrauma.

Brain Injuries↗
PubMedDate not supplied

Effects of triethyltin on ingestive behavior at ad lib, reduced, and recovered body weight.

The effects of repeated injections of small amounts of the neurotoxicant triethyltin (TET) on 1 and 24 hr food and water intake were investigated in rats at ad lib feeding, reduced, and recovered body weights. Following adaptation to 15% ethanol vehicle injections, TET doses of 0.5, 1.0 and 1.5 mg/kg body weight were administered in four separate injections, each separated by 3 or 4 days. Decreases only in 24 hr food intake and body weight occurred with 1.5 mg/kg TET in ad lib feeding animals. In animals reduced to 80% body weight decreases in water intake occurred for only 1 hr after injections of 1.0 or 1.5 mg/kg TET. When TET was administered to animals previously reduced to 80% body weight and allowed to recover ad lib feeding weight, effects on daily food and water intakes were observed. The effects of TET on ingestive behavior seem to be dependent on whether or not animals are or have been chronically food deprived. Results are discussed in terms of the known effects of TET on brain physiology.

Analysis of Variance↗
PubMedDate not supplied

Effects of triethyltin on schedule dependent and schedule induced behaviors under different schedules of reinforcement.

The subacute effects of triethyltin (TET) on operant responding and adjunctive behavior were assessed using either a fixed ratio (FR-30) or fixed interval (FI-1 min) schedule of reinforcement. Response rate decreased for rats on the FR-30 schedule given 1.5 mg/kg whereas animals on the FI-1 min schedule showed decreases in presses and pellets obtained at 1.5 mg/kg and in water intake at 1.0 and 1.5 mg/kg. When the animals on the FI-1 min schedule were allowed to recover body weight, decreases in presses, pellets obtained, licking, and water intake occurred at 0.5, 1.0 and 1.5 mg/kg. Schedule induced and schedule dependent behaviors were affected by low doses of TET. Rats at recovered body weight were most sensitive and affected by the lowest TET doses.

Analysis of Variance↗