Preparation and characterization of ß-lactoglobulin hydrolysate-iron complexes.

The purpose of this study was to determine the best preparation condition of ß-lactoglobulin hydrolysate-iron complexes and characterize its structural transformation both before and after binding using the UV-visible absorption spectrum, Fluorescence spectrum, and Fourier transform infrared spectroscopy. Results showed that ß-lactoglobulin hydrolysates obtained with alcalase after hydrolysis for 6h possessed the highest iron-binding capacity. The highest yield of complexes was obtained when the mass ratio between ß-lactoglobulin hydrolysate and Fe(3+) reached 40:1, with the optimal pH value of 7.0. All of the spectra indicated that some sites such as amido bonds transformed during chelation, and nitrogen atoms could chelate with Fe(3+) to form coordinate bonds by offering electron pairs. Therefore, ß-lactoglobulin hydrolysate-iron complexes may be good carriers for iron and possess great potential to be used as iron supplements.

[Evoked responses of visceral nociceptive neurons in cat anterior cingulate gyrus revealed by intracellular recording techniques].

With intracellular recording techniques, we investigated evoked responses and electrophysiological properties of neurons in anterior cingulate gyrus (ACG) to stimulating greater splanchnic nerve (GSN) in cats. Among 461 neurons, 176 were stimulus-relative and 285 stimulus-irrelative. According to the characteristics of the evoked responses, stimulus-relative neurons were classified into specific visceral nociceptive neurons (SVNNs, 64.77%), non-specific visceral nociceptive neurons (NSVNNs, 19.32%) and non-visceral nociceptive neurons (NVNNs, 15.91%). Modes of the evoked responses could be excitatory, inhibitory, or mixed ones. The results suggest that ACG may be one of the representative areas of the GSN afferent pathway, and there exist two kinds of VNNs in ACG, which may be differently involved in pain modulation.

[Electrophysiological and morphological characteristics of the visceral nociceptive neurons in cortex S II area of cats].

Electrophysiological and morphological properties of the visceral nociceptive neurons (VNNs) in the secondary somatosensory cortex (SII) area of 16 cats were investigated with intracellular recording and labeling method. Electrophysiological properties of a total of 251 neurons were identified, 109 of which were induced to discharge by stimulating the greater splanchnic nerve and therefore were simply designated as VNNs. Various patterns of the response could be recorded: excitatory (38.53%), inhibitory (42.20%) and excitato-inhibitory (19.31%). Following acquisition of electrophysiological data, neurobiotin was injected into 21 cells by electrophoresis to show their morphology and distribution in the cerebral cortex. It was found that excitatory VNNs were pyramidal neurons predominantly, whereas more inhibitory VNNs were stellate neurons.

[Intracellular electrophysiological characteristics of visceral nociceptive neurons in cortex S I area of cats].

In the present work we investigated electrophysiological properties of visceral nociceptive neurons in the primary somatosensory cortex (SI). Intracellular recordings of 851 neurons in the representing area of greater splanchnic nerve (GSN) in SI area were made in 22 cats. The neurons showed a variety of modes in spontaneous discharges, which could be classified into visceral nociceptive neurons (VNNs) and non-visceral nociceptive neurons (NVNNs). VNNs (412) could be further divided into specific and non-specific subtypes, with three distinct response modes: excitatory, inhibitory, and mixed response. These responses were characterized by longer latency and complex responsive fashion. In addition, 85 single convergence neurons induced by input from GSN and intercostal nerve were observed. Neurobiotin was injected into some of the cells by electrophoresis to identify the depth and morphology following recordings. The results indicated that VNNs were located in the SI area.

[Measurement of central motor conduction time (CMCT) in healthy Chinese subjects].

Transcutaneous electrical stimulation of the central nervous system was used to measure CMCT between the human cerebral cortex and spinal cord. 64 normal volunteers (46 healthy adult males and 18 females, age of 20-67 years, body height of 156-185 cm) were recruited as experimental subjects. Action potentials of muscles were recorded from upper limb (Thenar) and lower limb (Muscle tibialis anterior) following cortical and spinal stimulation. The cortical and spinal latent periods (Lcor., Lsp.) were measured and CMCT was obtained by subtracting Lsp. from Lcor. for each muscle. The CMCT between the cerebral cortex and the first thoracic (Th1) cord was 6.69 +/- 1.48 ms, while that between the cerebral cortex and the first lumber (L1) cord was 12.90 +/- 1.59 ms. Statistical analysis indicated that CMCT was not related to sex, age, body height and left or right side of the body as well. The motor conduction velocity in spinal cord (MCVsp) between Th1 and L1, [distance (Th1 to L1)/CMCT (Muscle tibialis anterior)-CMCT (Thenar)] was found to be 71.34 +/- 10.89 m/s, which corresponds to the conduction velocity of the large fibers in the pyramidal tract. The results of the present study are valuable in diagnosis and prognosis of motor system diseases in CNS.