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Biomedical subjects

M Funakoshi

Publications and source records attributed to M Funakoshi.

At least 91 records · Page 5Linked to original sources
PubMed1983

Relations between the spontaneous firing rate and taste responsiveness of the dog cortical neurons.

The breadth of responsiveness and the spontaneous discharge rates of dog cortical neurons to 4 taste stimuli (NaCl, tartaric acid, sucrose and quinine-HCl) were examined and compared to thalamic neurons. Spontaneous rates were higher in the cortex, and there was a smaller breadth of responsiveness. There were common tendencies observed in both thalamus and cortex; more narrowly tuned taste neurons and neurons having inhibitory responses had higher spontaneous rates. However, as shown by across-neuron correlations, the ability of cortical neurons to discriminate among the 4 tastes was less influenced by the level of spontaneous activity than thalamic neurons.

Animals↗
PubMed1983

Effects of androgens on the activity of steroid-metabolizing enzymes in the murine submaxillary gland.

Effects of androgens on the activity of androgen-metabolizing enzymes have been investigated in the murine submaxillary gland. 5 alpha-reductase activity is androgen-dependent, and 17 beta-hydroxysteroid dehydrogenase activity is androgen-resistant. The level and androgen-responsiveness of 5 alpha-reductase in the murine submaxillary gland are not imprinted during the neonatal period by testicular androgens. Circulating androgen may have a cumulative effect on androgen response of 5 alpha-reductase.

17-Hydroxysteroid Dehydrogenases↗
PubMed1982

Gustatory neural response in the mouse.

Gustatory responses from the mouse chorda tympani nerve were tested with various chemical solutions. Magnitudes of integrated chorda tympani responses to the 4 basic taste stimuli were greater in the order of HCl, sucrose, NaCl and quinine-HCl. Sucrose was the most effective sugar tested, while NaCl was the least effective salt, but divalent chloride salts were prominently effective stimulants. Many of single chorda tympani fibers responded specifically to one or two of the 4 basic taste stimuli. Single fibers sampled were classified into the following 5 types: sweet-type, Na-type, Ca-Mg-type, acid-type and quinine-type.

Animals↗
PubMed1982

Relationships between spontaneous discharge rates and taste responses of the dog thalamic neurons.

Response characteristics to the 4 taste stimuli (NaC1, tartaric acid, sucrose and quinine-HCl) and spontaneous discharge rates of taste neurons in the dog thalamus were examined. Response patterns of 72 thalamic neurons were somewhat complex, involving excitation (on type, on-off type and off type) and inhibition (short-term type and long-term type). A comparison among the responses to the 4 taste stimuli renders low response discharge rates and a high incidence of inhibitory responses to quinine-HCl. Measuring of the breadth of responsiveness showed that the thalamic taste neurons have varying sensitivities to the 4 taste stimuli and neurons responding best to quinine-HCl were more broadly tuned than those to each of the other 3 stimuli. These neurons also have varying spontaneous discharge rates and showed some relationship between the spontaneous rates and responses to taste stimuli. Neurons which showed inhibitory responses to stimuli have relatively high spontaneous rates. Neurons with higher spontaneous rates tend to be more narrowly tuned to the 4 taste stimuli. These relationships appeared not only as a general tendency of all the thalamic neurons but also as a characteristic of each of the 3 individual neurons which changed the spontaneous rates and breadth of responsiveness during long time recordings of neural discharges.

Action Potentials↗
PubMed1982

Responsiveness of dog thalamic neurons to taste stimulation of various tongue regions.

Receptive fields of single thalamic taste neurons in dogs were studied by examining responses to stimuli representing the four basic taste qualities applied to five different regions on the tongue surface. Twenty single thalamic units responded to taste stimulation of the tongue ipsilateral to the recording site were classified into three types according to characteristics of their receptive fields. In 11 out of 20 units, the location and the size of the receptive field and the most sensitive region in the receptive field did not vary among their effective taste stimuli (type A units). In 5 units, the location and the size of the receptive field varied with taste stimulus, although the most sensitive region was common to the stimuli (type B units). In the remaining 4 units, the most sensitive region varied with taste stimulus (type C units).

Afferent Pathways↗
PubMed1981

Dynamic-static sensitivity of rat chorda tympani fibers to anodal current applied to the tongue.

Responses of rat single chorda tympani fibers to anodal current of varying rise rates and current intensities applied to the tongue were examined. Thirteen out of fifteen chorda tympani fibers were sensitive to both rate of current rise and current intensity. However, sensitivities to these two stimulus parameters were different among 13 fibers. The remaining two fibers were not sensitive to the rate of current rise, but sensitive to current intensity. It was suggested that sensitivity to the rate of current rise was independent from that to current intensity.

Animals↗
PubMed1981

Role of the subsequently activated receptors in electro-acupuncture of the rat.

Role of the subsequently excited receptors elicited by tetanic muscular contraction in electro-acupuncture analgesia was examined. Conditioning stimulation of the nerve (CPN) as well as electro-acupuncture induced a significant delay of the tail flick latencies of the rat with weak intensity of stimulus (1.0-1.5 x DFT), and this effect was abolished after section of the nerve at a point distal to the stimulating electrode. Electrophysiological data indicate that a small amplitude of the A large fiber group's potential was recorded with the intensity range of 1.0-1.5 x DFT. These facts suggest that the analgesic effect induced by weak stimulation is not the result of direct excitation of afferent fibers but the result of subsequent activation of receptors provoked by tetanic muscular contraction. The possible receptors are proposed and their participation in acupuncture analgesia also discussed. CPn = the common peroneal nerve; DFT = dorsal flexion threshold (1.0 x DFT = 1.15 x Ta).

Acupuncture Therapy↗
PubMed1981

Taste response in the facial nerve of the carp, Cyprinus carpio L.

The stimulating effect of taste substances on the external chemoreceptors of the carp, Cyprinus carpio L., was studied by recording the electrical activity from the facial taste fibers innervating the facial skin surface. The integrated responses from each whole nerve bundle of the trigemino-facial complex nerve revealed that gustatory receptors on the snout of the carp were extremely sensitive to salts, acids and the extract of silk worm pupae. Quinine-HCl and sucrose elicited relatively small responses. Responses occurred to several amino acids, and especially to betaine. The threshold concentration for both mono- and di-valent salts was estimated to be about 5 X 10-3 M and that for acids about 10-4 M. Single fiber analysis was performed on 77 preparations. According to responsiveness to the 4 basic chemicals, the fibers were classified into 5 types: type I, activated by one stimulus (22 fibers out of 77); type II by two (29); type III by three (11); type IV by four (13); and type V showing inhibition by quinine-HCl (2) as their notable feature. Single fibers responsive to several amino acids, and the worm extract were found, among which the last was the most effective stimulus as shown in the whole nerve experiments.

Animals↗
PubMed1981

Responses of rat chorda tympani fibers to electrical stimulation of the tongue.

Responses of rat chorda tympani fibers to stimulations of the tongue with linearly rising anodal currents of varying rise rates and intensities, cathodal currents and chemical solutions representing the four basic taste qualities were obtained. Single fibers were classified into four types according to their response patterns to anodal and cathodal current stimulations of the tongue. Type A1 fibers responded only to an anodal current with both transient and steady response phases. Type A2 fibers responded only to an anodal current with only a steady response phase. Type B fibers responded to both anodal and cathodal currents. Type C fibers responded only to a cathodal current. Sensitivity to the rate f anodal current rise varied widely among individual chorda tympani fibers. The NaCl-sensitive fibers were most sensitive, the tartaric acid-sensitive fibers next, and the sucrose-sensitive fibers least. Fibers responding to cathodal current were sensitive to quinine hydrochloride. Fibers which showed rhythmic bursts of discharges in response to chemical stimuli also gave a similar discharge pattern in response to electrical stimulation.

Animals↗
PubMed1981

Role of ions in generation of taste nerve responses to electrical tongue stimulation in rats.

The role of ions in the generation of taste nerve responses to electric currents was studied by examining integrated responses and single fiber discharges of the chorda tympani nerve to chemical and electrical stimulations of the tongue in rats. Integrated chorda tympani responses to anodal currents were suppressed after cessation of the blood flow to the tongue and on application of FeCl3 to the tongue surface. These findings indicate that electric currents do not stimulate the nerve directly but activate taste cells to evoke neural discharges. Magnitude of the integrated response to anodal current decreased with a decrease in concentration and with an increase in flow rate of the bathing solution applied over the tongue during electrical stimulation. All the chorda tympani fibers responsive to a certain electrolyte responded to anodal or cathodal current in the presence of the same electrolyte at its subliminal concentration in the flow chamber. However, there were a few fibers which did not respond to a few electrolytes, but responded to currents in the presence of either one of the electrolytes even at their much lower concentrations. Across-fiber correlations between the responses to chemical stimuli and anodal currents in the presence of the chemical solutions in the flow chamber indicated that responsiveness to anodal current was not always dependent on species of cation in the bathing solution. From these findings, we assume that the response to electric current is due to the effect of electrophoretically carried ions on not only specific but also non-specific receptor mechanisms for the ions.

Action Potentials↗
PubMed1980

Comparison of chemoreceptions of terminal buds and pit organs of the carp, Cyprinus carpio L.

Neural responses to several chemicals of the pit organs and terminal buds on the facial skin of the carp were compared electrophysiologically. Nerve inpulses from the pit organs were larger than those from the terminal buds. The pit organs were more sensitive to salts and especially acids than the terminal buds. The former did not respond to sucrose, silk worm pupa extract, betaine and amino acids except acidic ones. The latter, however, responded well to them.

Animals↗
PubMed1980

Neurophysiological demonstration of an acupuncture point in man.

Relationship between an acupuncture point and the nerve fascicle was demonstrated electrophysiologically. A tungsten microelectrode was inserted to the acupuncture point Chu-Tse percutaneously in an awake human subject. When the subject experienced the particular sensation of Teh-chi, nerve impulses were recorded simultaneously. Electrical stimulation (5 Hz, biphasic pulse, 15 min) applied to the point through the electrode increased the pain threshold of the face and palm (147--171% of the control). These facts indicate that some of the acupuncture points located on the nerve fascicle and mechanical stimulation to the nerve fascicle play a part in the production of the Teh-chi sensation.

Acupuncture Therapy↗