Litorin and litorin-albumin conjugate as effective regulators of body temperature in rats.

Intraperitoneal injection of the bombesin-like peptide litorin (0.5 ml of a 10(-5) M solution) led to a short-lived decrease in the body temperature (maximum of 0.9 degrees C) of laboratory rats. In contrast, immunization with litorin conjugated to bovine serum albumin (BSA) led to an increase in body temperature from 36.6 +/- 0.1 to 37.2 +/- 0.1 degrees C that persisted for at least 4 weeks and which was probably due to the binding of endogenous litorin by the newly formed antibody. These results suggest that litorin is involved in the physiological regulation of thermal homeostasis. The temperature of control rats immunized with Freund's adjuvant and BSA without litorin fluctuated around normal at 36.6 +/- 0.1 degrees C over this period. Rat body weight increased evenly during the experiment in both the experimental animals and the two control groups. However, the volume of food intake in the hour following 24 h food deprivation was lower in rats immunized with conjugated litorin than in the control groups.

[Intake of water and sodium chloride solution by the rats after central administration of litorin and immunization with litorin-bovine serum albumin conjugate]. / Potreblenie vody i rastvora povarennoi soli krysami posle tsentral'nogo vvedeniia litorina i pri immunizatsii ikh kon"iugatom litorina s bych'im syvorotochnnym al'buminom.

Central injection of litorin suppressed water and sodium chloride solution intake, and also decreased the preference of saline of unrestrained rats during 1 hour test. Active immunization of animals with litorin-bovine serum albumin conjugate led to the augmentation of their daily saline preference. Immunized rats increased also avidity to salt after deprivation, though the consumption volume of liquids decreased. The data, obtained on the immunized animals prove the importance of definite level of endogenous bombesin-like peptide in the salt appetite of rats. The central effect of litorin is discussed in the aspect of changing by it the evaluation of gustatory information.

[Specific changes in the sodium chloride intake and activity of the taste receptor apparatus of rats administered the peptide litorin and its albumin conjugate]. / Spetsificheskoe izmenenie protsessa potrebleniia khlorida natriia i aktivnosti vkusovogo retseptornogo apparata u krys v usloviiakh vvedeniia peptida litorina i ego kon''iugata s al'buminom.

The role of bombesin-like peptide litorin in control of salt consumption was studied in rats. The influence of exogenous injection and binding of the endogenous litorin in the organism on the consumption of sodium chloride and sucrose solutions was analyzed in deprived rats in the process of 15-min. testing. It was found that intraperitoneal injection of 10(-6) - 10(-5) M of litorin led to an increase, and rats immunization by peptide conjugate with ox serum albumin--to a decrease of the consumption of salt solution, without changing the consumption of sucrose solution. Titres of antibodies to litorin in the plasma of rats immunized with the conjugate were higher than in the control. Intraperitoneal, subcutaneous or intranasal injections of 10(-5) M of litorin led to selective increase of gustatory responses (recorded from the chorda tympani) to tongue stimulation by salt and acid solutions not influencing the responses to quinine and sucrose in anesthetized rats. The study shows, that the peptide litorin selectively participates in the control of sodium chloride consumption. In the process of such control the increase of taste apparatus sensitivity to the sodium chloride is probably involved.

[Pharmaco-histochemical study of monoamine-containing cells in the taste buds as affected by capsaicin-induced substance P deficiency]. / Farmako-gistokhimicheskoe issledovanie monoaminsoderzhashchikh kletok vkusovykh pochek v usloviiakh defitsita veshchestva P, vyzvannogo kapsaitsinom.

A clearly positive correlation between the level of substance P (SP) in the taste nerves and cellular serotonin content in the taste buds has been established using fluorescent-histochemical technique. In chronic SP deficiency caused by capsaicin, cellular serotonin content was considerably decreased due to the disturbances in its synthesis and uptake. The injection of exogenous SP resulted in the recovery of the initial serotonin level. The data obtained confirm an important role of SP in the maintenance of the optimal cellular serotonin level owing to the activation of monoamine synthesis and uptake.

[Histoarchitectonics of the cholinergic innervation of the frog tongue]. / Gistoarkhitektonika kholinergicheskoi innervatsii iazyka liagushki.

Acetylcholinesterase (AChE) activity was studied in dorsal tongue surface structures and in both tongue nerves (hypoglossal and glossopharyngeal) of frogs (Rana temporaria). AChE was found in nerve fibers of fungiform and filiform papillae, blood vessels, glandular ducts of tongue mucosa, both nerve fibers and also in the bodies of cholinergic neurons in subepithelial connective tissue and along the glossopharyngeal nerve. Their parasympathetic origin was suggested. The experiments with butirilthiocholin have revealed no activity of non-specific cholinesterases in the above structures. Possible role of cholinergic system in the regulation of tongue receptor function is discussed.

[Effect of taste deafferentation on the preference for solutions of saccharose, saccharin and salt in rats]. / Vliianie vkusovoi deafferentatsii na predpochtenie rastvorov sakharozy, sakharina i soli u krys.

The preference of sucrose, saccharin and salt solutions to water was analyzed during 5 days in rats with bilateral section of the lingual nerve comprising the taste nerve--chorda tympani. In the process of the analysis of daily consumption and choice of solutions, different types of behavioural reactions were found: stable preference and change of preference. The number of rats preferring NaCl was greater among the animals with sectioned lingual nerve than among sham-operated control rats and rats with ligated ducts of submaxillary and sublingual salivary glands. The number of rats with the lingual nerve section preferring sucrose or saccharin solutions to water was equal to that among the sham-operated rats. At the same time the mean volume of sucrose solution taken in daily by rats with sectioned lingual nerve was twice as great as the volume of saccharin, drunk by the same animals. The role of taste in the process of choice and preference of NaCl to sweet solutions is discussed.

[Activating effect of cholecystokinin-pancreozymin on the taste-receptor system of the rat]. / Aktiviruiushchee vliianie kholetsistokinina-pankreozimina na vkusovoi retseptornyi apparat krys.

The effect of the intraperitoneal injection of 10(-5) M cholecystokinin-pancreozimin solution on the taste total impulse activity of the rat chorda tympani was studied. The taste responses to sodium chloride and sucrose increased within 5 min and responses to quinine increased within 30 sec after the peptide injection. Responses to citric acid solution did not augment significantly. The augmentation of the taste responses under peptide injection can be blocked by cutting the chorda tympani nerve or subepithelial administration of atropine solution.

[Effect of substance P on the monoamine-containing cells of the taste buds]. / Vliianie substantsii P na monoaminsoderzhashchie kletki vkusovykh pochek.

The effect of substance P (SP) on monoamine-containing cells of the frog taste buds was studied by fluorescent microscopy. Intraperitoneal injection of SP resulted in a gradual increase of cell serotonin content. In monoamine deficiency caused by previous injection of rausedyl, SP favoured the recovery of the serotonin level to initial. When SP and rausedyl were used combined, SP protected the serotonin-containing cells from the depleting effect of rausedyl. The functional role of SP in the taste apparatus is discussed.

[Effect of antibodies against tubulin on the activity of taste receptors]. / Vliianie antitel protiv tubulina na aktivnost' vkusovogo retseptorogo apparata.

Electrophysiological studies were carried out to investigate the effect of monospecific tubulin antibodies on the activity of the receptor gustatory apparatus of Rana temporaria under adequate stimulation of receptors with NaCl and glucose solutions and water. There was a significant decrease in receptor responses to NaCl and water stimulation after administration of antibodies. Glucose responses were less prone to the effect of antibodies. The authors discuss the mechanism of the involvement of the microtubules-tubulin system found in receptor formations into the peripheral mechanisms of chemoreception.

[Significance of serotonin in the activity of the taste receptor apparatus of the frog Rana temporaria]. / O znachenii serotonina v deiatel'nosti vkusnogo retseptornogo apparata liagushki Rana temporaria.

Studies have been made of the effect of exogeneous serotonin on responses of taste receptors recorded from the hypoglossal nerve during adequate stimulation. It was shown that serotonin evokes afferent discharge in this nerve and significantly increases responses of taste receptors. Stimulating effect of serotonin appears 15-20 min after its application and gradually develops reaching maximum within 60 min after injection. Competitive antagonist of serotonin, 7-methyltryptamine, inhibits taste afferent responses and blocks stimulating effect of serotonin. Possible role of serotoninergic mechanism in afferent impulse activity of the taste receptive apparatus is discussed.

[Electrical response of frog lingual epithelium to stimulation of the gustatory nerve]. / Elektricheskaia reaktsiia épiteliia iazyka liagushki na razdrazhenie vkusovogo nerva.

Electrical stimulation of the gustatory nerve evoked a positive electrical response of the outer surface of the tongue (relative to its inner layers). The amplitude and the rate of rise of the response grew and the latency fell with increased frequency of stimulation. The response originated in the superficial epithelial layer (30-60 micrometers) and was produced by a decrease of "resting potential" (negative-outside) of this layer. The response was accompanied by a strong decrease of the superficial tongue layer resistance and arose probably as a result of short-circuiting of the epithelial layer by high-conductive nonspecific channels. Similar response accompanied by a decrease of the superficial tongue layer resistance was recorded with adequate stimulation (by acetic acid vapours). The results are compared with the response of the frog skin to the stimulation of cutaneous nerve.

[Development of the chemo- and mechanoreceptors of the tongue in mature-born animals (scanning electron microscopy)]. / Stanovlenie khemo- i mekhanoretseptornykh obrazovanii iazyka zrelorozhdaiushchikhsia zhivotnykh (élektronnaia skaniruiushchaia mikroskopiia).

Scanning electron microscopy was used to study developmental changes in the chemo- and mechanosensory apparatus of the tongue in guinea-pigs, goats and sheep during the 1st to the 10th postnatal week. The maturation of the chemosensitive postnatal formation of the mechanosensitive papillae was shown.

[Effects of colchicine, cyclic nucleotides and biogenic amines on the chemoreceptor apparatus of the tongue]. / Vliianie kolkhitsina, tsiklicheskikh nukleotidov i biogennykh aminov na khemoretseptornyi apparat iazyka.

Colchycine considerably decreased sensitivity of the Rana temporaria tongue's chemoreceptors to adequate stimulation. The effect is reversible and can be abolished by administration of drugs initiating setting of the cells' microtubular apparatus: 3',5'-cAMP, theophylline, adrenaline as well as by activation of the sympathetic system. The restoring effect of these agents is specific since 2',3'-cAMP, 5'-AMP, serotonin, inosine, acetylcholine and 3,'5'-cGMP prove ineffective in restoring the reactions after colchycine administration although they do alter the activity of the receptors in normal conditions. The revealed colchycine-sensitive, 3',5'-cAMP-dependent process seems to be associated with the microtubular apparatus of the receptor cell. Its role in the receptor structures is discussed.

[Recovery of colchicine-blocked chemoreceptor reactions of the frog tongue as affected by electrical stimulation of the sympathetic nervous system]. / Vosstanovlenie zablokirovannykh kolkhitsinom reaktsii khemoretseptorov iazyka liagushki pod vliianiem élektricheskogo razdrazheniia simpaticheskoi nervnoi sistemy.

Under adequate stimulation of tongue chemoreceptors with feeds synchronous recording of the total afferent impulse activity of the glossal branches of Rana temporaria glossopharyngeal nerves was used to demonstrate the facilitation effect of electric stimulation of the I sympathetic ganglion on the receptor reactions in health and after treatment with colchicine provoking a considerable weakening of the reactions. The data are discussed in the light of the adaptation-trophic effect of the sympathetic system at the level of molecular-metabolic intracellular processes. No poisoning effect of alkaloid on the sympathetic fibers has been recorded.

[Possible role of sympathetic influences and cAMP in centrifugal inhibitory control of the gustatory receptor apparatus]. / O vozmozhnoi roli simpaticheskikh vliianii i tsAMF v tsentrobezhnom tormoznom kontrole vkusovogo retseptornogo apparata.

The electrophysiological analysis of the taste total impulse activity of the rat revealed the inhibitory influence of the gastric distention on the salt and sour taste responses to be decreased by cutting of the neck sympathetic nerve and prevented by the propranolol injection into the taste epithelium. Salt and sour taste responses were diminished by the injection of isoproterenol, cAMP, dibutyril--cAMP, and the inhibitors fo phosphodiesterase theophilline and paraverine; the activator of phosphodiesterase nicotine acid increased the taste responses. The finding suggest that the adrenergic transmitters and cAMP take part in the actualization of the inhibitory centrifugal influences.