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1. We used extracellular recording of the infrared (IR)-sensitive trigeminal ganglion (TG) neurons (primary neurons) of a crotaline snake, Trimeresurus flavoviridis, which has very sensitive thermoreceptors, to examine changes in the IR response induced by dimethylsulfoxide (DMSO), in vivo. 2. The responses in the TG were recorded after each concentration of DMSO (1, 10, and 25%) was administered in the bloodstream. 3. At a constant temperature, DMSO dose-dependently potentiated the IR-triggered discharges of IR-sensitive TG neurons in this snake. 4. It is suggested that the increased IR response to DMSO is due to its chemical effect, or to an indirect effect via its vasoactive role in the thermoreceptors of IR-sensitive snakes.

The infrared receptor neurons of Python reticulatuspit organs were all found to have bimodal sensitivity, responding to both infrared and touch stimuli with fairly rapid adaptation. The majority (22 of 29 neurons) had no background discharges at any temperature between 20 and 33°C. The receptive areas were 150–250 µm in diameter and identical for both modalities. There was only one receptive area for each neuron. These facts suggest the possibility that some kinds of temperature sensitive neurons can also function as touch neurons and vice versa, not only in this species, but also in other animals.

Afferent impulses from single-fiber preparations of the trigeminal nerve in Agkistrodon blomhoffi brevicauduswere recorded during steady and dynamic temperature stimulation of the sensory membrane in the facial pit. The thermoreceptors of the pit showed high sensitivity to the rate of change in receptor temperature. Changing the heat capacity of the pit membrane (a drop of water in the pit in the case of the laser and halogen lamp, and a drop of water covered by a plastic film in the case of flowing water) changed the pattern of response. When the heat capacity of the pit membrane is increased, responses approach those obtained in other warm receptors. The spatial gradient theory of Williams, whereby a reversal of heat energy flow is supposed to produce a reverse of response, was shown to be inapplicable to the pit receptors. Reversal of heat energy flow in the pits produced neither off-silence nor depression of response, and therefore direction of heat flow is not an important component of the stimulus for these receptors.

Thirty-five touch (M) neurons and 59 vibrotactile (V + M) neurons were recorded intrasomally in the trigeminal ganglion of a crotaline snake (the pit viper, Trimeresurus flavoviridis). The M neurons were excited by von Frey hair (5-10 mg) mechanical stimulation of the receptive field, and adapted slowly to a sustained stimulus. It was almost impossible to elicit 1:1 entrainment to sinusoidal movement. Vibration with touch was an adequate stimulus for the V + M neurons. The range of entrainment to sinusoidal movement was 5-300 Hz. Thresholds of V + M neurons to sustained mechanical stimulation could not be determined, but a response was obtained by stroking with a von Frey hair (5-10 mg). Receptive fields of both M and V + M neurons were found on the skin (scales) and the mucous membrane of the orofacial region. There was one receptive field of ∼2 mm in diameter for each M or V + M neuron.The mean resting potentials (± SD) of M and V + M neurons were -57.0 ± 5.1 mV (n = 26) and -63.7 ± 8.2 mV (n = 49), respectively. Neurons of both modalities displayed no background discharge. The action potential of V + M neurons had a shorter mean duration than that of M neurons. The mean conduction velocities (± SD) of peripheral (and stem) axons of M and V + M neurons were 28.4 ± 5.7 m/sec (n = 11) and 30.8 ± 7.8 m/sec (n = 30), respectively.Recorded neurons were labeled with intrasomal horseradish peroxidase electrophoresis. V + M neurons had larger somata than M neurons. All axons of M and V + M neurons were myelinated and similar in diameter. M and V + M neurons had similar central projection patterns. The projection of the thick central axon divided into a thinner ascending fiber and a thick descending fiber at the entry zone of the root to the brainstem. The former ran ipsilaterally to the principal sensory nucleus of the trigeminal nerve (TPR), and the latter ran to the descending nucleus of the trigeminal nerve (TTD) and beyond, where terminal arbors and bouton swellings were observed. Smaller myelinated and unmyelinated collaterals were given off at right angles from the descending fiber of the central axon into the TTD. They projected more densely to the rostral part than to the caudal part of the TTD.All of these data were compared with data on warm-temperature neurons, previously obtained.

1. Intrasomal recordings of potentials produced by current stimulation in vivowere made from 24 (A-β) touch and 19 vibrotactile neurons in the trigeminal ganglion of 29 crotaline snakes, Trimeresurus flavoviridis. 2. Usually touch neurons responded with a single action potential at the beginning of a prolonged depolarizing pulse, whereas all vibrotactile neurons responded with multiple spikes. 3. The electrophysiological parameters examined were membrane potential, threshold current, input resistance and capacitance, time constant, rebound latency, and its threshold current. Touch neurons had higher input resistance (and lower input capacitance) than vibrotactile neurons. 4. In conclusion, current injection, which elicits a single or multiple spiking, seems a useful way to separate touch neurons from vibrotactile neurons without confirming the receptor response, and some membrane properties are also specific to the sensory modality.

[3H]2-Deoxy-d-glucose (2-DG) and high-resolution autoradiography were employed to investigate labeling patterns of the trigeminal and infrared sensory system in acrotaline snake, the pit viper (Trimeresurus flavoviridis). Following intracardiac injection of 9.25 MBq [3H]2-DG, neurons in the nucleus of the lateral descending trigeminal tract (LTTD), nucleus reticularis caloris (RC), nucleus trigemini mesencephalicus, nucleus trigemini motorius, and trigeminal ganglia were labeled in various degrees after the pit organ had been removed (basal condition). This revealed that a higher rate of glucose utilization occurred in these nuclei than in the common sensory trigeminal nuclei, which lacked labeling entirely. When a pit was stimulated periodically with an infrared stimulus for 45 min, the difference in percentage of labeled cells was ipsilaterally increased by 12.84% in large cells of the LITD and by 7.55% in the RC, as compared with the contralateral, basal-condition side. These slight changes indicate a small increase of glucose consumption during infrared reception. On the other hand, the small cells in the LTTD showed labeling that did not change with stimulation, suggesting that 2-DG uptake in inhibitory interneurons is relatively constant.

By observing ultrastructural changes under the electron microscope, we illustrated exocytosis and recycling of vesicles in the infrared receptor, a kind of free nerve ending in the pit organ of the crotaline snake, Trimeresurus flavoviridis. While maintaining the snake pit organs at stable temperatures of 15°C, 25°C, and 30°C, we fixed them by perfusion and then processed them for transmission electron microscopy. The largest number of clear and coated vesicles appeared in the terminals at the lowest temperature. The perimeter and area of a terminal were enlarged at 30°C, and "opening waves" on the plasma were prominently found at the highest temperature. We also observed coated vesicles that budded from the plasma membrane in the terminals. The configuration of mitochondria in the terminals was quantitatively different between lower and higher temperatures. The data suggest that exocytosis and endocytosis in these terminals operate in a manner similar to that observed in other cell types.

Both action potentials and evoked potentials were recorded from the tectum opticum of a crotaline snake, Trimeresurus flavoviridis, in response to infra-red stimulation of the facial pit organs. Action potentials from single units were recorded throughout the tectum. Most units responded to contralateral stimulation, while some responded to both ipsi- and contralateral stimulation. Firing patterns were tonic, phasic, or phasic-tonic, depending on the position of the stimulus and the type of unit being recorded. Sensitivity to stimulus movement was observed. All potentials differed from peripheral potentials in firing patterns. Firing frequency was directly proportional to stimulus intensity. Measurements were made of the vertical and horizontal response fields of single units. Background discharge was noted in all units and its nature discussed. The integrative function of the tectum in regard to infra-red perception was also discussed, as well as the possibility of stereoscopic perception.

A new amino acid named galantinamic acid was found as one of the constituent amino acids in a peptide antibiotic galantin I. The primary structure of galantinamic acid was determined chemically and spectrometrically to be 6,10-diamino-2,3,5-trihydroxydecanoic acid.

Opinion. Presents an individual's view on the financial sector of Japan. Details on the corrupt practices taking place in the financial sectors; Information on bankers who ask government financial officers for favors; Reference to Japan's Ministry of Justice.

Opinion. Examines the implications of sociological concepts on the economic condition of Japan. Conflict between Japan's concept of society with Western concept; Focus of the Japanese on the concept of shame; Acceptability of Japanese practices in international law.