AIMTo investigate the possible central mechanism of antipyretic effects of Chinese medicine gypsum.

METHODSGypsum was injected after the fever model was established. The firing rate of thermosensitive neurons in preoptic-anterior hypothalamus(PO/AH) region was recorded by using extracellular microelectrode technique.

RESULTSThe injection of pyrogen evoked decrease in firing rate of the warm-sensitive neurons and increase in the cold-sensitive neurons in the region of PO/AH; the changes of the firing rate of pyrogen- treated warm-sensitive and cold-sensitive neurons could be reversed by the injection of gypsum.

CONCLUSIONThe result may suggest that antipyretic action of gypsum is mediated by its influences on the thermosensitivity neurons in the region of PO/AH.

Action Potentials ; Animals ; Antipyretics ; pharmacology ; Calcium Sulfate ; pharmacology ; Cats ; Fever ; physiopathology ; Hypothalamus, Anterior ; physiopathology ; Male ; Materia Medica ; pharmacology ; Neurons ; physiology ; Preoptic Area ; physiopathology ; Pyrogens

Animals ; Antioxidants ; pharmacology ; Female ; Hypoxia ; physiopathology ; Male ; Mice ; Panax ; chemistry ; Random Allocation ; Reperfusion Injury ; prevention & control ; Saponins ; isolation & purification ; pharmacology

AIMTo compare the thresholds of auditory brain-stem response (ABR) and frequency characteristics in five normal rodent species: CBA, BABL/c, C57BL, KunMing mice and guinea pigs.

METHODSAuditory brain-stem responses in four species of mice and guinea pigs were investigated with IHS-SmartEP 3.91 system. The thresholds and characteristics of ABR in each frequency were measured by the stimulated sound of tone-pip. Acoustic frequency-threshold curves in these five rodent species were made. The optimal response frequencies were assessed.

RESULTSThe thresholds of guinea pigs were the lowest in five rodent species, and KunMing mice, CBA mice, BALB/c mice, C57BL mice in turn. All the thresholds of ABR in these experimental animals were the lowest in 10 kHz. The thresholds became increasing in higher frequency (> 10 kHz), and in lower frequency (< 10 kHz). This was a common characteristic in frequency threshold curves of ABR in these five rodent species.

CONCLUSIONThe hearing of guinea pigs was the best in these five rodent species. The hearing of KunMing mice was sharper than those of the other mice. Stimuli of 10 kHz was the optimal frequency in these live rodent species, and the optimal frequency range was from 8 kHz to 24 kHz.

Acoustic Stimulation ; Animals ; Audiometry ; Auditory Threshold ; physiology ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Female ; Guinea Pigs ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Inbred CBA ; Species Specificity

AIMTo increase the cognition of cerebellar functions and the knowledge of neuroimmunology, the effect of cerebellar interposed nuclei (IN), one of three deep nuclei in cerebellum, on lymphocyte function was investigated.

METHODSKainic acid (KA) was microinjected into bilateral IN for lesions of neuronal bodies in the IN. Control rats was microinjected with saline into their IN. On days 8, 16 and 32 following the IN lesions, the lymphocyte number in the peripheral blood was measured by blood corpuscle counter. Meanwhile, lymphocyte proliferation induced by concanavalin A (Con A), cytotoxicity of natural killer (NK) cells against YAC-1 cells, and anti-SRBC IgM antibody in the serum were examined respectively by methyl-thiazole-tetrazolium (MTT) assay, flow cytometry and ELISA assay.

RESULTSThe lymphocyte number in the peripheral blood was significantly reduced on days 8, 16 and 32 following the effective lesions of the bilateral IN in comparison with that of control. The Con A-induced lymphocyte proliferation, the NK cell cytotoxicity to YAC-1 cells, and the titer of anti-SRBC IgM antibody in the serum, were all significantly attenuated on days 8, 16 and 32 following the effective lesions of the bilateral IN in comparison with those of control. There were not remarkable differences between the days 8, 16 and 32 in the decreased lymphocyte number and functions induced by the lesions of the bilateral IN.

CONCLUSIONEffective lesions of the cerebellar bilateral IN of rats cause an inhibition in lymphocyte number and functions of T, B and NK cells, strongly showing that the cerebellar IN can modulate lymphocyte functions.

Animals ; Cerebellar Nuclei ; immunology ; physiology ; Cerebellum ; immunology ; physiology ; Female ; Kainic Acid ; Killer Cells, Natural ; immunology ; Lymphocyte Count ; Lymphocytes ; immunology ; Male ; Microinjections ; Neuroimmunomodulation ; immunology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

AIMTo observe the change of potassium current on cultured neurons differentiated from hippocampus neural stem cells of the newborn rat.

METHODSNeural stem cells from newborn rat hippocampus were cultured in vitro and passaged continuously. Differentiation of the cell was induced by serum and removing mitogens. After differentiation cells were plated on plastic dishes and cultured for 1 d, 7 d, 14 d and 21 d. Whole-cell voltage patch clamp recording was used respectively to detect voltage-dependent K+ current.

RESULTSAfter 1 d culture, no current was detected, and on the 7th d, 14th d, 21st d after differentiation, the amplitude of K+ currents was (18.077 +/- 2.789)pA/pF, (13.099 +/- 2.742)pA/pF, (34.045 +/- 8.067)pA/pF at +50 mV. The recorded K+ current included two components that could be blocked by TEA and 4-AP separately, assumed the slowly inactivating delayed rectifier K+ current (IK) and the fast inactivating transient outward K+ current (IA).

CONCLUSIONThe function of potassium channels on the hippocampus neural stem cells of the newborn rat approaches mature gradually when the time of differentiation becomes longer in vitro.

Animals ; Animals, Newborn ; Cells, Cultured ; Delayed Rectifier Potassium Channels ; physiology ; Hippocampus ; cytology ; Neural Stem Cells ; cytology ; metabolism ; physiology ; Patch-Clamp Techniques ; Potassium Channels ; physiology ; Potassium Channels, Inwardly Rectifying ; physiology ; Rats ; Rats, Sprague-Dawley

AIMTo explore the relationship between evoked potentials (EPs) and chronic anoxic brain damage by chronic intermittent hypoxia (CIH), and provide theory evidence for diagnosis and treatment of anoxic encephalopathy.

METHODSBAEP and SLSEP were recorded in rat model with CIH (hypoxia group) and rat with normoxia (normal group). Morris water maze was used to observe learning and memory ability. Immunohistochemical method was used to investigate the expression levels of caspase-3 in brain tissue.

RESULTSThe peak latency (PL) of wave I, III, V and the interpeak latency (IPL) of wave III - V, I - V in BAEP in hypoxia group were much longer than that of in normal group (P < 0.05). The PL of wave N1, P1 of SEP in hypoxia group were much longer than that of in normal group (P < 0.05). In the water mase test, the escape latency (EL) of hypoxia group was much longer than normal group (P < 0.01). The number of caspase-3 positive cells in hypoxia group was much larger than that of in normal group (P < 0.05). There was a positive correlation among BAEP, SLSEP, the number of caspase-3 positive neuron and EL of water mase.

CONCLUSIONThe alteration of BAEP and SLSEP has an apparent correlation with chronic anoxic brain damage. This provides theory evidence for diagnosis and treatment of anoxic encephalopathy.

Animals ; Brain ; enzymology ; pathology ; physiopathology ; Caspase 3 ; genetics ; metabolism ; Chronic Disease ; Evoked Potentials, Auditory, Brain Stem ; physiology ; Evoked Potentials, Somatosensory ; physiology ; Hypoxia, Brain ; physiopathology ; Male ; Maze Learning ; Random Allocation ; Rats ; Rats, Sprague-Dawley

AIMTo investigate the mechanisms of Naoyikang (Traditional Chinese Medicine) on the Alzheimer's Disease (AD) model mice induced by D-galactose (D-gal) and NaNO2.

METHODSThe mouse model was established by intraperitoneal injection of D-gal and NaNO2. The capacity of learning and memory was tested on mice with electrical maze; the content of nitric oxide (NO) and the activity of monoamine oxidase-B (MAO-B), glutathione peroxidase (GSH-PX), Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme in cerebral cortex and hippocampus were assayed by biochemical methods; expression of Bax and Bcl-2 mRNA was detested by RT-PCR.

RESULTSNaoyikang could ameliorate the capacity of learning and memory of AD model mice and reduce MAO-B activity in the brain tissue and activate the activity of Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme in the brain tissue and decrease the expression of Bax mRNA, but increase the expression of Bcl-2 mRNA in the model brain tissue.

CONCLUSIONNaoyikang could protect AD model mice induced by D-gal and NaNO2. It could modify the metabolism of monoamine neurotransmitter in brain through reducing MAO-B activity and protect neurons by activating the activity of Na(+) -K(+) -ATP enzyme and Ca(2+) -ATP enzyme and decrease Bax expression and increase Bcl-2 expression in the model brain tissue.

Alzheimer Disease ; chemically induced ; drug therapy ; Animals ; Disease Models, Animal ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Galactose ; Male ; Maze Learning ; Mice ; Mice, Inbred ICR ; Neuroprotective Agents ; therapeutic use ; Phytotherapy ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Sodium Nitrite ; Sodium-Potassium-Exchanging ATPase ; metabolism ; bcl-2-Associated X Protein ; genetics ; metabolism

AIMTo establish the method of long-term potentiation (LTP) recording in hippocampus in anaesthetized mice in vivo.

METHODSMouse was anaesthetized and then placed in the stereotaxic apparatus. The recording electrode was located at the cell body layer of dentate granule cells and the stimulating electrode at the perforant path according to stereotaxic parameters. Then the LTP was evoked and recorded.

RESULTSAfter optimizing of experimental factor, the LTP in PP-DG path in anaesthetized Balb/c mice was successfully recorded. The changes of synaptic plasticity were also observed in SAMP8 and SAMRI by using the optimized method. The results were coincident with the behavioral tests and LTP in hippocampal slices that we reported before.

CONCLUSIONThe method of LTP recording in vivo in hippocampus in anaesthetized mice was successfully established and could be used to evaluate the synaptic plasticity in vivo.

Anesthesia ; Animals ; Electric Stimulation ; Electrodes ; Evoked Potentials ; physiology ; Hippocampus ; physiology ; Long-Term Potentiation ; physiology ; Male ; Mice ; Mice, Inbred BALB C ; Neuronal Plasticity ; physiology ; Stereotaxic Techniques ; Synaptic Transmission ; physiology

Animals ; Cycadopsida ; chemistry ; Down-Regulation ; drug effects ; Female ; Flavones ; isolation & purification ; pharmacology ; Isoproterenol ; Male ; Myocardial Ischemia ; chemically induced ; metabolism ; prevention & control ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism

AIMTo observe the effect of stretching left ventricles in the end of action potential on rabbit cardiac activity, and to investigate its possible mechanisms.

METHODSStretch (120 mmHg, 50 ms) was applied in the end of action potential by the pressure-clamp technique to observe if there would be any changes in rabbit cardiac activity and streptomycin (500 micromol/L) was used to identify the mechanism.

RESULTSStretch in the end of action potential caused arrhythmia (P < 0.05) and streptomycin blocked the above effect (P < 0.05).

CONCLUSIONStreptomycin could block the effect of stretching left ventricles in the end of action potential on rabbit cardiac activity, which indicates that stretch-activated ion channels involve it.

Action Potentials ; physiology ; Animals ; Arrhythmias, Cardiac ; etiology ; physiopathology ; Female ; Heart Ventricles ; physiopathology ; In Vitro Techniques ; Ion Channels ; physiology ; Male ; Mechanoreceptors ; drug effects ; Proprioception ; Rabbits ; Streptomycin ; pharmacology