Activities of somatosensory relay neurons responding to orofacial mechanical stimulation were examined in the ventrobasal complex of the thalamus (VB) and in the trigeminal main sensory nucleus (MSN) during EEG desynchronization in urethane-anesthetized rats. EEG desynchronization was induced by scrotal warming in a temperature range of 35-40 degrees C. Responses of most VB neurons to receptive-field stimulation were augmented during EEG desynchronization, when compared to responses during synchronization. Spontaneous activity of VB neurons also increased with EEG desynchronization. Responses of MSN neurons to receptive-field stimulation did not change appreciably when the EEG pattern was altered. If a VB neuron was induced by iontophoretic application of glutamate to fire at the same rate as seen during EEG desynchronization, a similar increased response to receptive-field stimuli was also observed. The augmented response of the VB neuron during desynchronization may thus have resulted from increased excitability of the neuron itself.

Animals↗

PubMed1986

Grooming, body extension, and vasomotor responses induced by hypothalamic warming at different ambient temperatures in rats.

During heat stress, rats extend their body and spread saliva onto their body surfaces (grooming) for evaporative heat loss in addition to tail vasodilation. We investigated the effects of changing hypothalamic (Thy) and ambient (Ta) temperatures on these thermoregulatory responses. The higher the Ta, the lower the Thy at which grooming started when Ta was changed from the thermoneutral zone (24 degrees C) to 28-40 degrees C. At any Ta grooming was induced only when the posterior hypothalamic region (PH) was warmed by implanted diathermy. Grooming was more strongly induced at a Ta of 28 degrees C than at 24 degrees C. At a Ta of 32 degrees C, PH warming evoked body extension as well, decreasing the duration of grooming as compared to that at 28 degrees C. Warming the preoptic area and anterior hypothalamus induced body extension and tail vasodilation regardless of Ta. The data suggest that grooming was induced by integrated temperature signals from the PH and from the peripheral skin.

Animals↗

PubMed1986

Effect of periaqueductal morphine injection on thermal response in rats.

The effect of morphine injection into the midbrain periaqueductal gray (PAG) was examined on thermal response in rats. Rectal temperature (Tre) was recorded in unanesthetized and unrestrained animals before and after PAG morphine injection of 5 or 10 micrograms in cold (10 degrees C), neutral (22 degrees C), and hot (34 degrees C) environments. Both doses of morphine caused hyperthermia. Sixty to 105 min after the injection, Tre rose by 1.0-1.5 degrees C regardless of ambient temperature. Naloxone (2 mg/kg, i.p.) blocked the hyperthermic effects of morphine. Injection sites producing hyperthermia were distributed mostly in the ventral PAG and its ventral environs. The analgesic effect of morphine was examined by the tail-flick test. Locations of morphine injection effective for producing analgesia were restricted to the ventral area of the region responsible for hyperthermia. Magnitude of the hyperthermia did not significantly differ between animals with or without analgesia. The effect of PAG morphine (5 micrograms) was tested on tail vasomotor response to hypothalamic and scrotal thermal stimulations in urethane anesthetized (1.0 g/kg) animals. Threshold hypothalamic temperature for the vasodilation was lower at a scrotal temperature of 40 degrees C than at 30 degrees C. Following PAG morphine, threshold hypothalamic temperature rose and the difference in threshold hypothalamic temperature at the two scrotal temperatures disappeared.

Animals↗

PubMed1985

Brain NADH and jumping behavior in the rat.

The effects of either the reduced Nicotinamide Adenine Dinucleotide (NADH) microinjected into the brain or amphetamine injected peritoneally on jumping behavior were observed in 68 rats. The enhanced jumps in the group with amphetamine are the greatest among the three experimental groups. The enhanced effect of NADH microinjected into the caudate nucleus is stronger than those of NADH in the frontal cortex. The effects of extra NADH in the frontal cortex on the jumps are dose-dependent. NADH concentrations in the brain of rats with amphetamine increased immediately after behavioral procedure. The increased concentrations in the brain from both extra and intra sources are related to the enhanced jumps of rats.

Amphetamine↗

PubMed1984

[Studies on the physical structure and pharmaceutical properties of aluminum hydroxide tablets].

Explore the source record for details and available documents.

Aluminum Hydroxide↗

PubMed1982

Transfer of radiation-induced spins from deoxyribonucleic and thymidylic acids to propyl gallate.

When calf thymus deoxyribonucleic acid (DNA), propyl gallate (PG) and their five molecular mixtures (with PG content of 1, 2, 5, 10 and 20%) are irradiated with gamma-rays in dry state in vacuum at 296 degrees K, the ESR spectra of all molecular mixtures differ strikingly from those of DNA, but bear a close resemblance to those of PG. The spin yield in the PG contained in these mixtures is two to three orders of magnitude higher than that in the case of PG irradiated separately. Furthermore, on the basis of the relative saturation characteristics of ESR spectra, these molecular mixtures behave more like PG than like DNA. It may be inferred that the radiation-induced spins could be transferred from DNA to PG. With r representing the molar ratio of nucleotides to PG, we have found a good linear correlation between the transfer ratio (TR) and square root of r. One PG molecule could protect at least 68 nucleotides in the duplex DNA chain, and thereby the minimal range of spin transfer is estimated at 115 A. Results obtained from irradiation at 77 degrees K show that PG exerts no protective effect on DNA, so DNA sustains an irreversible damage. It is thought that the spin transfer from DNA to PG is exclusively due to a hydrogen transfer mechanism. We have also demonstrated the transfer of radiation-induced spins from both thermally denatured DNA and TMP to PG. The former process can be ascribed primarily to the hydrogen transfer mechanism, whereas the latter, as in the case of native DNA, exclusively to this mechanism.

Animals↗

PubMedDate not supplied

Image enhancement of the in vivo leukocyte-endothelium contact zone using optical sectioning microscopy.

A major determinant of the strength of leukocyte [white blood cell (WBC)] to endothelium [endothelial cell (EC)] adhesion is the contact area formed between the two cells, which is often obscured by out-of-focus information inherent to intravital microscopy. To improve visualization of the WBC-EC contact zone, techniques of optical sectioning microscopy were developed to enhance brightfield images of WBC-EC adhesion in postcapillary venules of the mesentery of the rat. A 50x/1.0 NA objective was held in a piezoelectric mount that was computer-driven, and video images were obtained by digitizing images from a CCD camera while focusing through the vertical direction in 1 micron steps over a depth of 16 microns. Using measurements of the microscope's optical transfer function, deconvolution of the central image was performed in the Fourier domain using the technique of singular value decomposition with Tikhonov-Miller regulation to remove out-of-focus information. Measurement of the length of the WBC-EC contact zone (LC) in the original images yielded values on the order of 4.32 +/- 1.08 microns (mean +/- SD). The enhanced images showed a significantly 35% smaller LC equal to 2.78 +/- 0.70 micron. Topical application of the chemoattractant f-met-leu-phe resulted in a 26% increase in LC to 3.49 +/- 0.72 micron, thus suggesting that upregulation of adhesion molecules on the WBC membrane results in the recruitment of additional membrane area from surface ruffles into the zone of adhesion. Other advantages of the deconvolution were to visualize structural characteristics of the microvascular wall and parenchymal tissue in greater detail. Thus, brightfield optical sectioning microscopy may provide a valuable tool for in vivo studies of the microvasculature, and serves as a useful alternative to fluorescence microscopy without the undesirable effects of exogenous fluorophores and exposure to ultraviolet radiation.

Algorithms↗