Intracellular responses of neurons in the trigeminal spinal nucleus oralis were studied in chloralose-anesthetized cats. Twenty neurons, shown to be second-order neurons, were classified into two groups based on the pattern of responses to single shocks applied to the frontal, infraorbital and inferior alveolar nerves, each belonging to one of the three principal divisions of the trigeminal nerve. One group consisted of 9 neurons and responded with an EPSP and a few spike potentials followed by an IPSP (Type I) . The other group consisted of 11 neurons and responded with a rather long-lasting EPSP superimposed often by a burst of spikes (Type II) . No IPSPs were detected in Type II neurons.
Four of Type I neurons responded antidromically to stimulation of the contralateral thalamic ventral posteromedial nucleus (VPM) (Type I projection neurons), and the remaining 5 Type I neurons responded orthodromically to the VPM stimulation (Type I non-projection neurons) . In contrast, Type II neurons responded only orthodromically to the VPM stimulation.
Type I neurons, especially Type I projection neurons, usually received excitatory inputs from one of the above-mentioned nerves, had a receptive field innervated by the same nerve, and received inhibitory inputs from the other nerves as well as from outside the receptive field. However, Type II neurons received excitatory inputs from more than one nerve, and showed no inhibitory responses to peripheral stimulation. An IPSP-EPSP sequence was evoked in four of Type I neurons by stimulation of the face region of the contralateral somatosensory cortex; three were projection neurons and the remaining one was a non-projection neuron. On the contrary, IPSPs were evoked in none of Type II neurons by the cortical stimulation.
The results demonstrate that postsynaptic processes are involved in the central and peripheral inhibitory modulation of synaptic transmission in the trigeminal sensory nucleus.

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Repetitive electrical stimulation of the mesencephalic reticular formation (MRF) in ketamineanesthetized guinea pigs induced a rhythmical jaw movement (RJM) resembling mastication. The RJM was monitored by the multiple unit activity in the anterior digastric motoneuron pool (DIGMUA) as well as by the EMG activity simultaneously recorded from the masseter and anterior digastric muscles on both sides.
The following results were obtained: 1. The RJM induced by the MRF stimulation was characterized by a large opening movement to the contralateral side than that which was induced by stimulation of the cortical masticatory area (CMA) . 2. The RJM induced from the medial MRF was accompanied by a well coordinated tongue movement, but that which was induced from the lateral MRF was accompanied by no tongue movements. 3. The cycle time of the RJM induced from the medial MRF was definitely longer than that induced from the CMA, but there was no difference between the RJM induced from the lateral MRF and that which was induced from the CMA. 4. The rhythmical activity of the masseter EMG appeared in phase bilaterally, as was that of the anterior digastric EMG. The EMG activities of both muscles appeared reciprocally during the RJM induced from the CMA, but they partially overlapped during the RJM induced from the lateral MRF. The medial MRF stimulation induced the digastric EMG activity alone. 5. After the animal was paralyzed, the MRF stimulation induced a rhythmical DIG-MUA in essentially the same pattern as before paralysis. 6. After the CMA-induced rhythmical masticatory activity (RMA) was abolished by a complete lesion of the pyramidal tract at the pontine level on both sides, the MRF stimulation could induce the same pattern of RMA as before the lesion. 7. After a precollicular postmammillary transection was performed, the MRF stimulation induced the same RJM as before the transection.
Microinjectionof L-glutamate into the lateral MRF induced the same RMA as that which was induced by electrical stimulation of the same region in the MRF.
It was concluded that stimulation of the MRF neurons can induce the RMA centrally with no intervention of either the upper brain including the CMA or the peripheral feedback afferents, and that the effect of MRF stimulation is mediated to the lower brain stem by a route other than the pyramidal tract. In addition, the MRF is assumed to be mainly activated from the upper brain including the feeding center in the hypothalamus as well as the limbic system.

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The purpose of this study was to investigate the relationship between the severity of the periodontal disease and the defective neutrophil chemotaxis in the patients with Down's syndrome (D.S. patients) .
Fourteen D. S. patients (9 males, 5 females, 12 to 34 years in age) were examined using the Plaque Control Record (O'Leary), Gingival Index (Löe & Silness), probing pocket depth and dental radiographs. The neutrophil chemotaxis in the D.S. patients and 14 healthy volunteers was measured with the agarose plate method modified by our laboratory and Boyden chamber method.
The results showed that the chemotactic index by the agarose plate method and the number of migration cells by the Boyden chamber method were significantly correlated (r=0.627, p<0.01) and the neutrophil chemotaxis in the D.S. patients was significantly impaired when compared with the healthy volunteers (p<0.01) . The neutrophil chemotaxis in 50 per cent of the D.S. patients was lower than the normal range of the healthy volunteers. No difference could be demonstrated between the D.S. patients and the healthy volunteers in the random migration of neutrophil.
From the radiographic analysis, three groups were divided according to the bone loss, which consisted of less than 4 parts, 4 to 6 parts and more than 6 parts of the upper and lower jaws (10 parts) . The patients with a high bone loss showed significantly a lower chemotactic index of neutrophil, whereas the D.S. patients with a slight bone loss showed almost a normal chemotactic index.
These results suggested that the defective neutrophil chemotaxis was one of the pathogenetic factors of destructive periodontal disease.

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Proteoglycans in a smaller size present in the bone and dentin are considered to play some role in the differentiation and calcification. The purpose of this study is to characterize the biochemical and immunological properties of the bone and dentin proteoglycans, especially their core proteins.
The proteoglycans were extracted with EDTA/guanidine HCl from the bovine bone and dentin and purified by the DEAE-Sephacel and Sepharose CL-6B chromatography. The purified proteoglycans were digested with chondroitinase ABC and the core proteins from the dentin proteoglycan were used to raise the monoclonal antibody.
Both the bone and dentin proteoglycans were found to contain glycosaminoglycan and protein in equal amounts. The core proteins of the bone proteoglycan were shown to consist of 45 K, 40 K and 35K in molecular weight, whereas those of the dentin were 90K, 70K, 40K and smaller. The proteoglycan core proteins of 40 K and smaller sizes in the dentin were immunologically similar not only to those of the bone but also to those of the cartilage, tendon and dental pulp.

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