Modulation of neuron activity of the midbrain periaqueductal gray matter influenced by monoaminergic brainstem structures

A study was done on base activity and changes in base activity (BA) of neurons in periaqueductal gray matter (PAG) during stimulation of monoaminergic structures of the brainstem: the nucleus raphe magnus (NRM), the locus coeruleus (LC), and the substantia nigra (SN), in rats anesthetized with hexenal (200 mg/kg). Three types of PAG neurons that differed in BA structure were identified. NRM, LC and SN stimulation changed BA only in type III neurons. Stimulation of these structures evoked an increase in BA frequency in 11.0–14.5%, and inhibition in 31.0–47.5% of type III neurons. Simultaneous stimulation of two structures led to a marked drop in intensity of effects. A depressing effect on BA was always detected if stimulation of one of the structures suppressed BA. Stimulation of two structures, with one being the NRM, was most effective. The role of PAG in the organization of the brain-stem component of the antinociceptive mechanism is discussed.A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vol. 24, No. 1, pp. 52–60, January–February, 1992.     

Effect of stimulation of the caudate nucleus on activity of neurons of the globus pallidus

Activity of neurons of the globus pallidus was recorded extracellularly during stimulation of the caudate nucleus. It is demonstrated that background activity (BA) of most neurons of the globus pallidus is depressed under these conditions, which is regarded as a manifestation of inhibition of the investigated neurons. The period of BA depression varied in different cells from 60 to 500 msec. In some cases this period was preceded by emergence of an action potential with a latent period of 10–20 msec. In addition to inhibition of the activity of globus pallidus neurons during stimulation of the caudate nucleus, it was possible to record evoked responses of the given neurons in the form of group discharges with a latent period of 18–40 msec and single action potentials with a latent period of 50–100 msec. The neurons that reacted with a shorter latent period were localized at the lateral limit of the globus pallidus, whereas neurons with other kinds of responses were distributed in the globus pallidus comparatively evenly.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 1, No. 2, pp. 202–209, September–October, 1969.     

Changes in the background activity of neurons of the central gray substance when serotonin is applied to it or its synthesis is blocked

The changes in the background activity (BA) of neurons of the central gray substance upon the iontophoretic application of serotonin (ST) to them in a concentration of 1·10^–4 mole/liter, and following the blockage of its synthesis by pchlorophenylalanine (PCPA), were investigated in hexenal-anesthetized rats. The application of ST led to changes in the BA only in group III neurons, in which the BA was distinguished by continuous action potential generation. The application of ST elicited an increase in the frequency of the BA in 21.2% of such neurons, suppression in 45.5%, and the BA remained unchanged in 33.3% of the units. The identified changes in the BA in these neurons coincided with those which arose as the result of stimulation of the monoaminergic structures. When the application of ST was combined with stimulation of the locus coeruleus (LC), the substantia nigra (SN), and the nucleus raphe magnus (NRM), the suppression of the BA was intensified; however, when the LS and the SN were stimulated, the suppression was more pronounced than with stimulation of the NRM. The intensity of the suppressant effect of the NRM decreased after preliminary administration of PCPA, but it did not disappear completely, and the influences elicited by the LS and the SN intensified. The mechanisms of the serotoninergic control of the activity of the neurons of the central gray substance are discussed.A. A. Bogomolets Institute of Physiology, Ukrainian Academy of Sciences, Kiev. Translated from Neirofiziologiya, Vo. 24, No. 2, pp. 169–177, March–April, 1992.     

Comparative analysis of background activity of ventrolateral thalamic neurons in patients with parkinsonism and torsion muscle dystonia

In the course of neurosurgical interventions in 40 patients with parkinsonism and torsion muscle dystonia, the background activity (BA) was recorded from 124 neurons of the ventrolateral nucleus (VL) of the thalamus with the aid of microelectrodes during demarcation of boundaries between nuclear structures, and identification of zones within a nucleus. The following characteristic features of the BA in patients with parkinsonism were found: a relatively large proportion (71%) of cells with a burst pattern of activity; a great diversity of burst duration in the activity (short or prolonged bursts); a large proportion (67%) of cells with cyclic changes in the BA frequency; diverse patterns of cyclic modulation, where periods varied from fractions of a second (0.2–0.8 sec) to seconds (2–10 sec) or to tens of seconds (20–40 sec); cyclic successions of spike bursts with the rhythm typical of the peripheral tremor (3–7/sec) in a substantial proportion (40%) of the units.The background spike trains recorded in patients with torsion muscle dystonia consisted of separated spikes in the majority (69%) of units. Only short high-frequency discharges were found in the burst activity in this group; a cyclic BA pattern occurred much less frequently (in 23% of neurons); burst discharges at a 3–4/sec frequency were found only in 4% of the examined cells.The possible nature of motor disorders in patients with parkinsonism and torsion muscle dystonia and the mechanisms of the curing effects of cryodestruction of theVL of the thalamus in the treatment of the disease are discussed.Neirofiziologiya/Neurophysiology, Vol. 25, No. 4, pp. 246–253, July–August, 1993.     

Background activity of the rabbit superior cervical ganglion neurons: Soundness of random hypothesis of its formation

The soundness of hypotheses interpreting the mechanism of formation of background activity (BA) generated by the neurons of the rabbit superior cervical ganglion was analyzed, taking into account the statistical characteristics of this activity. These neurons are supplied with a multiple synapic input. According to the random hypothesis, the BA action potentials in the ganglion neurons result from occassional coincidence of the spikes arriving through independent presynaptic inputs. Our calculations showed that the frequency of BA action potentials observed in the experiments is too high to be explained by the random hypothesis and needs synchronization of firing in different presynaptic neurons, rather than their independent firing.Neirofiziologiya/Neurophysiology, Vol. 28, No. 1, pp. 47–52, January–February, 1996.     

Effect of Long-Lasting Vibration on the Impulse Activity of Neurons of the Inferior Vestibular Nucleus

We analyzed the impulse background activity (BA) of neurons of the inferior vestibular nucleus (IVN) of rats during exposure to long-lasting vibration (daily 2-h-long sessions). It was demonstrated that 5 days after the beginning of vibration stimulation, practically all main characteristics of the BA of IVN neurons changed significantly. In the studied neuronal group, 10 days after the vibration onset we observed an increase in the mean frequency of the BA and shifts in many statistical parameters of the BA, while after 15 days of vibration only significant modifications of dynamic characteristics of the BA of IVN neurons were manifested.Neirofiziologiya/Neurophysiology, Vol. 37, No. 1, pp. 32–38, January–February, 2005.     

Principal component analysis of evoked neuronal firing pattern in the human brain

Evoked firing activity (EFA) in neurons of the human thalamic reticular nucleus (Rt) was recorded by microelectrodes using extracellular recording techniques in the course of stereotaxic surgery for dyskinesia. Activity was induced by functionally significant verbal and sensory stimuli together with performance of goal-directed behavioral actions (BA). Use of the principal component method and construction of peristimulus covariance matrices are suggested in view of the presumably convergent nature of EFA in Rt neurons, taking the form of superposing independent components of response and variability in these in the course of BA testing and performance for the purpose of analyzing EFA and interneuronal correlations. The multivariate pattern of Rt EFA time courses during the action of functionally significant stimuli was revealed; this reflects different stages in performance of BA. The dynamics of components of response are revealed and occurrence of rapidly developing interneuronal correlations in functionally significant stages of goal-directed BA are described. Findings point to the efficacy of the suggested approach applied to analysis of EFA neurons.Institute of Chemical Physics, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 22, No. 6, pp. 811–818, November–December, 1990.     

Background activity of neurons of the dorsal spinocerebellar tract

We investigated background activity (BA) of neurons of the dorsal spinocerebellar tract (DSCT) during experimental limitation of the number of afferent inputs to these neurons. Complete unilateral deafferentation of the lumbar and sacral segments leads to total inhibition of the BA of most of the neurons of the DSCT, or to reduction of its frequency (not more than 4 impulses/sec) if it survives. With partial deafferentation of DSCT neurons, their BA can be divided into two types that differ with respect to interspike interval distribution (for type I >100 msec and >15 msec for type II <100 msec and <15 msec). It is hypothesized that the type of BA is mainly determined by the functional state of afferent inputs, viz., the presence or absence of activation of the neuron from afferents of group Ia. The presence of such activation leads to formation of BA of the second type. Analysis of the renewal density function and serial correlation coefficients reinforces the conclusion that BA of DSCT neurons is caused by their periodical activation from extension receptors, which receive considerably fewer regular synaptic influences from secondary afferent inputs and from interneurons. Following generation of an action potential in neurons of the DSCT there apparently develops an after subnormality, the accumulation of which at interspike intervals of less than 50 msec can lead to the appearance of negative serial correlation coefficients of the first order. When BA frequency is lower, serial correlation coefficients of the first order are positive.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 2, No. 1, pp. 26–34, January–February, 1970.     

Regeneration of `juvenile' plants of black plum,Syzygium cuminii Skeels,from nodal exp of mature trees

Nodal explants, excised from young shoots from mature trees of Syzygium cuminii, were cultured on MS medium supplemented with different concentrations of BA or kinetin. Among these, BA (0.5 or 1.0 mg l^–1) induced greening and opening of the incipient shoot buds, which however did not elongate. Elongation of the shoot buds was facilitated on MS medium with 1.0 mg l^–1 BA supplemented with casein hydrolysate (1.5 g l^–1) or glutamine (200 mg l^–1). Nodal explants (microcuttings), taken from shoots developed in vitro, also developed multiple shoots when cultured on MS with1 mg l^–1 BA. These explants did not require an additional supply of reduced nitrogen, for further normal development. Shoots developed from explants from mature trees and microcuttings were rooted by sub-culturing them on Knop's medium supplemented with 2% sucrose and 1 mg l^–1 IAA. The plants that developed in vitro were planted in soil and were transferred to the field after an acclimatization period of 7–8 months. These plants have been thriving well for more than three years and have no apparent phenotypic aberrations.     

Spike activity of fastigial cerebellar neurons in rat: Effects of stimulation of thelocus Coeruleus andn. raphe pontis

Effects of electrical stimulation of the brain stem aminergic structures,locus coeruleus (LC) andn. raphe pontis (RP), on spike activity of neuronal units of then. fastigius (NF) of the rat cerebellum were studiedin vivo. A significant number ofNF neurons was found to respond to the activation of inputs from theLC andRP, showing no dependence on the localization of the units within theNF and the level of their background activity (BA). The responses of theNF neurons were predominantly selective, i.e., evoked by stimulation of only one of the inputs. Convergent effects of uniform or reciprocal pattern were found less frequently. The effects of stimulation were rather variable, but inhibitoryLC andRP influences dominated. TheLC effects appeared in a greater proportion ofNF neurons, and facilitatory influences from this structure were more usual. The pattern of responses toLC orRP stimulation was variable; monocomponent responses were more frequent, but there were also bi-, tri,- and polycomponent responses. High variability of their latent periods, duration, and intensity was found. Considering six main types of BA ofNF neurons classified earlier [1], we showed thatNF neurons with the longest cycles of BA variation (with significant correlation coefficients on the order of 20 to 40 of the compared interspike intervals), as well as the neurons with burst activity are most intensively affected by theLC. BurstingNF neurons responded more intensively toRP stimulation. Effects ofLC orRP stimulations depended on the BA level. Equal proportions of the neurons with low (<40/sec) BA frequency were inhibited and facilitated byLC stimulation. Inhibitory effects prevailed in the neurons with intermediate (40/sec to 70/sec) or high (>70/sec) BA frequencies.Neirofiziologiya/Neurophysiology, Vol. 25, No. 6, pp. 446–455, November–December, 1993.     

Ongoing activity in identified neurons of the rat superior cervical ganglion before and after partial denervation of the submandibular gland

Ongoing activity was investigated in rat superior certical ganglion neurons innervating the submandibular gland using intracellular recording techniques. These cells had previously been labelled by fluorescent marker. Ongoing activity was found in 11% of test cells, with a firing rate of 0.1±0.01 Hz. No ongoing activity occurred in the remainder (89% out of 95). Following an experimentally induced reduction in the number of neurons innervating the gland (which had previously been partially denervated), numbers of cells manifesting ongoing activity rose significantly (from 11 to 42%) and ongoing spike rate rose, at 0.3±0.03 Hz. These changes in neurons innervating the partially denervated gland are thought to result from increased convergence on these neurons of influences from preganglionic fibers.Studies carried out at the Anatomy and Neurobiology Department of Washington University Medical School (St. Louis, USA).A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 21, No. 6, pp. 826–832, November–December, 1989.     

In vitro multiplication and microrhizome induction in Curcuma aromatica Salisb.

Shoot multiplication and plant regeneration was achieved from freshly sprouted shoots of Curcuma aromatica on Murashige and Skoog's medium supplemented with BA alone (1–7 mgL^–1) or a combination of BA(1–5 mgL^–1) and Kn (0.5–1 mgL^–1). A concentration of 5 mgL^–1 BA was optimum for shoot multiplication and rooting of shoots. The regenerated plants grew profusely on transfer to liquid medium.In vitro raised plants were successfully established in the field. Microrhizomes were induced at the base of the in vitro derived shoots upon transfer to medium containingvarious combinations and concentrations of sucrose and BA and grown under varying photoperiods. MS basal medium with 5 mgL^–1 BA, 60 gL^–1 sucrose and an8 h photoperiod was optimum for induction ofmicrorhizomes within 30 days of culture. Harvestedmicrorhizomes stored in moist sand in poly-bagssprouted after 2 months of storage at roomtemperature. For in vitro storage, microrhizomeswere grown in medium containing 0.1 mgL^–1 BA.Microrhizome formation was found to be controlled bythe concentrations of BA and sucrose as well asphotoperiod during culture.     

Induction and stimulation of in vitro flowering of Pharbitis nil by cytokinin and gibberellin

The influence of BA, GA₃ and IAA applied successively onflower bud formation in shoot apices of Pharbitis nil hasbeen investigated. The shoot apices were isolated from seedlings cultivatedunder non-inductive continuous light and from seedlings exposed to asubinductive (12 h) dark period. BA and GA₃ introducedsuccessively into culture medium replaced the inductive night, causing theflowering of plantlets in completely non-inductive continuous light (optimalconcentration of BA – 10^–7–10^–6mol dm^–3, GA₃ –10^–7–10^–6 moldm^–3) and stimulated this process under thesubthresholdinduction. These hormones applied in reverse sequence (in the first placeGA₃, then BA) did not affect flowering of explants. IAA nullifiedthestimulating effect of BA and GA₃. The influence of phytohormones onflowering may result from the change of growth correlations within the shootapical meristem.     

Effects of Immobilization Stress on the Background Impulse Activity of Locus Coeruleus Neurons

We studied in rats changes in the impulse background activity (BA) of locus coeruleus (LC) neurons after short- and long-term immobilization stress; distributions of LC neurons by the level of regularity of their BA, dynamics of spike trains, and pattern of histograms of interspike intervals (ISI) were taken into account. We also calculated the means of the main BA statistical indices. Both short- and long-lasting immobilizations resulted in drops in the mean frequency of background discharges of LC neurons to about half of the initial value. Two-hour-long immobilization evoked statistically significant shifts in the distribution of LC neurons by the level of regularity of their BA, while after longer (15 h) immobilization this distribution nearly returned to the initial pattern. Short-lasting immobilization exerted no significant effect on the dynamic characteristics of BA; statistically significant changes in this respect developed only after longer stress. After 15-h-long immobilization, we also observed a noticeable increase in the number of neurons with polymodal ISI distributions. Therefore, stress results in significant modifications of the temporal parameters of the BA of LC neurons; characteristics of the BA of these neurons should be considered neuronal correlates of the stress state.     

Efficient GA3-assisted plant regeneration from cell suspensions of three grape genotypes via somatic embryogenesis

Petioles from in vitro grown plants of interspecific grapevine hybrids cvs `Bianca', `Podarok Magaracha' and `Intervitis Magaracha' were cultured on solid NN medium supplemented with 2,4-D and BA at various concentrations. The callus developed was cultured in liquid NN medium supplemented with 0.5 mg l<sup>–1</sup> BA to induce formation of somatic embryos. Somatic embryos of globular and heart-stage developed in suspensions of `Podarok Magaracha' and `Intervitis Magaracha'. In contrast, `Bianca' did not undergo embryogenesis beyond globular stage. This made it necessary to perform subculture of the suspensions to HTE liquid medium supplemented with 0.2 mg l^–1 BA for the development of globular embryos into heart stage. Heart-stage embryos developed into torpedo-stage after subculturing suspensions of all three cultivars to liquid HTE medium supplemented with 0.1 mg l^–1 IAA and 30 mg l^–1 sodium hummate. Torpedo-stage embryo suspensions were subcultured in liquid HTE medium supplemented with 0.5 mg l^–1 BA, 0.5 mg l^–1 GA₃ and 0.5 mg l^–1 GA₃ + 0.2 mg l^–1 BA. After 12 days of incubation, plantlets were cultured on solid M2MS medium: without growth regulators and with 0.5 mg l^–1 BA. Plantlets that developed in liquid HTE media with 0.5 mg l^–1 GA₃ or 0.5 mg l^–1 GA₃ + 0.2 mg l^–1 BA produced 82–90% shoots on solid M2MS medium with 0.5 mg l^–1 BA after 50 days of culture.     

Plant regeneration through somatic embryogenesis from callus cultures of <Emphasis Type="Italic">Dioscorea zingiberensis</Emphasis>

A new method was established for somatic embryogenesis and plant regeneration from callus cultures of Dioscorea zingiberensis C.H. Wright. Primary callus was induced by culturing stems, leaves and petioles on Murashige and Skoog (MS) medium supplemented with 0.5–2.0 mg l^–1 N⁶-benzyladenine (BA) and 0–2.0 mg l^–1 -naphthaleneacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D) for 1 month. The highest frequency (87%) of callus formation was achieved from stem explants treated with 0.5 mg l^–1 BA and 2.0 mg l^–1 2,4-D. Somatic embryos were obtained by subculturing embryogenic calli derived from stem explants on MS medium supplemented with 2.0–4.0 mg l^–1 BA and 0–0.4 mg l^–1 NAA or 2,4-D for 3 weeks. The optimum combination of 4.0 mg l^–1 BA and 0.2 mg l^–1 NAA promoted embryo formation on one-third of the calli. After a further month of subculture on the same medium, mature embryos were transferred to MS medium supplemented with 0–4.0 mg l^–1 BA, NAA or indole-3-butyric acid (IBA) for further development of plantlets and tuber formation. Plant growth regulators had a negative effect on the development of mature embryos.     

In vitro plantlet regeneration from cotyledons of the tree-legume Leucaena leucocephala

Two plant regeneration methods applicable to Leucaenaleucocephala were developed. In the first method, involvingorganogenesis via callus formation, cotyledon, hypocotyl and root segments wereinitiated on MS medium containing different concentrations ofN⁶-benzyladenine (BA), 2,4-dichlorophenoxyacetic acid (2,4-D), andnaphthaleneacetic acid (NAA). Both compact (type I) and friable (type II) calliwere obtained from the cotyledon and hypocotyl explants treated with differentconcentrations of the growth regulators. Shoots were generated only from thefriable calli formed from the cotyledon explants. The calli formed from thehypocotyl explants did not generate shoots and the root explants died withoutforming callus. Cotyledon explants from 3–4 day old seedlings showedmaximum callus induction compared to those from older seedlings. In a secondmethod involving direct organogenesis, excised cotyledons were cultured on 1/2MS medium containing 10–35 mg l^–1N⁶-benzyladenine (BA) for 7–14 days. Transfer of thecotyledonsto regeneration medium containing low BA resulted in callus formation andsubsequent shoot regeneration from the base of the excised cotyledon explants,with up to 100% frequency. Regenerated shoots rooted best on a basal mediumcontaining no growth regulators.     

Plant regeneration via somatic embryogenesis from protoplasts of six plant species related to Citrus

Protoplasts isolated from embryogenic callus of Fortunella polyandra (Ridl.), Atalantia bilocularis (Pieree ex Guill.), Hesperethusa crenulata (Roxb.), Glycosmis pentaphylla (Retz.) Corr., Triphasia trifolia (Burm. f.) P. Wils. and Murraya koenigii (L.) Spreng. were cultured in MT (Murashige and Tucker 1969) basal medium containing 5% sucrose supplemented with 0.0, 0.001, 0.01, 0.1 or 1.0 mg l^–1 BA and 0.6 M sorbitol. The highest plating efficiencies for all species were obtained on MT basal medium containing 5% sucrose supplemented with 0.001 mg l^–1 BA. F. polyandra produced higher percentages of globular somatic embryo development, while A. bilocularis consistently showed a lower percentage of globular somatic embryo development in all 5 concentrations of BA. MT basal medium containing 5% sucrose and supplemented with 0.001 mg l^–1 BA was found to be a suitable medium for development of globular somatic embryos derived from protoplasts to form heart-shaped somatic embryos with cotyledon-like structures. The highest percentages of shoot formation for all 6 species were obtained using 0.1 mg l^–1 GA₃. A complete protoplast-to-plant system was developed for F. polyandra, A. bilocularis and T. trifolia, which could facilitate the transfer of nuclear and cytoplasmic genes from these species into cultivated Citrus through protoplast fusion.Abbreviations BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - FDA fluorescein diacetate - GA₃ gibberellin A₃     

Production of acetone,butanol and ethanol by Clostridium beijerinckii BA101 and in situ recovery by gas stripping

We examined the effect of gas-stripping on the in situ removal of acetone, butanol, and ethanol (ABE) from batch reactor fermentation broth. The mutant strain (Clostridium beijerinckii BA101) was not affected adversely by gas stripping. The presence of cells in the fermentation broth affected the selectivities of ABE. A considerable improvement in the productivity and yield was recorded in this work in comparison with the non-integrated process. In an integrated process of ABE fermentation-recovery using C. beijerinckii BA101, ABE productivities and yield were improved up to 200 and 118%, respectively, as compared to control batch fermentation data. In a batch reactor C. beijerinckii BA101 utilized 45.4 g glucose l^–1 and produced 17.7 g total ABE l^–1, while in the integrated process it utilized 161.7 g glucose l^–1 and produced total ABE of 75.9 g l^–1. In the integrated process, acids were completely converted to solvents when compared to the non-integrated process (batch fermentation) which contained residual acids at the end of fermentation. In situ removal of ABE by gas stripping has been reported to be one of the most important techniques of solvent removal. During these studies we were able to maintain the ABE concentration in the fermentation broth below toxic levels.     

Functional morphology of the neuroendocrine sodium influx-stimulating peptide system of the pond snail,Lymnaea stagnalis,studied by in situ hybridization and immunocytochemistry

Summary The functional morphology of the neuroendocrine system producing sodium influx-stimulating (SIS) peptide in the pond snail, Lymnaea stagnalis, was studied by in situ hybridization and immunocytochemistry. The SIS-peptide, which is 76 amino acids long, stimulates sodium uptake from the ambient medium. Two synthetic DNA probes were used for in situ hybridization. The nucleotide sequences were chosen from the cDNA structure; they encode amino acids 8–17 and 64–73, respectively. SIS-peptide sequences 10–20 and 67–76 were synthesized and antibodies were raised to them and affinity-purified. In addition to these antibodies, a monoclonal antibody raised to a bioactive, high-pressure liquid chromatography (HPLC)-purified brain extract was used for immunocytochemistry. Paraffin sections of central nervous systems and of whole snails were studied. The SIS-peptide system could be identified as the previously described yellow cell (YC) system by comparing alternate sections treated with the DNA probes, stained with the antibodies, or stained with alcian blue-alcian yellow. SIS-peptide neurons (45) occur in the ganglia of the visceral ring and in the proximal parts of visceral nerves. Axons run in the nerves of these and in several nerves of other ganglia. Numerous axon branches penetrate the perineurium forming a vast central neurohemal area. The SIS-peptide system innervates the pericardium, the nephridial gland, the reno-pericardial canal, the ureter, the spermoviduct and gonadal acini, the anterior aorta, the ventral buccal artery, and the penis protractor muscle. The morphology of the system is discussed in relation to the process of sodium ion uptake from the ambient medium and from pro-urine, and to that of regulating blood pressure. In the central nervous system and other organs, neurons and axons not labeled with the DNA probes, but immunoreactive to one or two of the antibodies, were observed. It seems unlikely that these elements are functionally related to the SIS-peptide system.