Functions of the Hypothalamo-Hypophyseal-Adrenal System in Aging in Female Monkeys

Comparative studies on the functioning of the adrenal cortex in female rhesus macaques (Macaca mulatta) of different ages are reported – animals were aged 6–9 years (young adults; n = 5) and 20–26 years (old adults; n = 5). Corticosteroid concentrations (cortisol (F) and dehydroepiandrosterone sulfate (DHEAS)) were determined by specific radioimmunological and immunoenzyme methods in basal conditions, after acute stress (insulin–induced hypoglycemia, 2–h movement restriction), and after administration of dexamethasone. Basal F levels showed no marked age differences, while DHEAS concentrations in older animals decreased sharply. These animals also demonstrated weakened adrenal cortex responses to movement restriction, giving rise to delays in reaching peak F and DHEAS levels and decreases in the areas under their response curves (AUC) during the 4–h study period. In the dexamethasone test, the hypothalamo–hypophyseal–adrenal system of monkeys aged 20–26 years was relatively resistant to the suppressing effect of glucocorticoids via the negative feedback mechanism. It is suggested that disruption of feedback in the system controlling adrenal cortex function may be at least partially due to the development of peripheral blood steroid dysbalance with aging, this consisting particularly of a decrease in the DHEA (DHEAS) level; this steroid is known for its neurological activity.     

Antigenic relationships among the 47 human adenoviruses determined in reference horse antisera

Summary Reference equine antisera to all 47 serotypes of human adenoviruses presently described have been prepared and evaluated by reciprocal neutralization and hemagglutination-inhibition tests. All tests were carried to endpoint dilutions a minimum of five times in each direction to give accurate values for homologous and heterologous antibody titers. Significant cross-reactions in the horse antisera were compared to similar data obtained from rabbit antisera. Using this analysis, major antigenic relationships exist among types 12–18–31 of subgenus A, types 7–11–14 and 34–35 of subgenus B, types 8–9–10, 10–19–37, 13–38–39, 15–22–42, 20–47, 24–32–33–46, and 29–45 of subgenus D, types 16-4 between subgenera B and E, and types 40–41 of subgenus F. Across all subgenera, types 8, 10, 13, 15, 17, 19, 26, 29, 39, 40, and 43 have antigenic moieties found most frequently in other types, averaging 12 heterologous reactions per type when summing both tests in both directions. Types 20, 30, 32, and 45 exhibit shared determinants slightly less often, with a mean of 8 heterologous reactions per type.     

The role of the cardiac nerves in the regulation of sodium excretion in conscious dogs

Conscious, chronically instrumented dogs, maintained on a high sodium intake, were used to investigate whether surgical cardiac denervation impairs the natriuresis associated with left atrial pressure increase produced in three ways: during an increase in left atrial pressure by means of a reversible mitral stenosis (protocol 1); after an i.v. saline load (1.0 ml 0.9%·saline min^–1·kg^–1 over 60 min) (protocol 2); after an oral saline load (14.5 mmol Na·kg^–1 given with the food as an isotonic solution) (protocol 3).During a reversible mitral stenosis, in intact dogs, urine volume and sodium excretion increased markedly (from 34–145 l·min^–1·kg^–1 and from 3–12 mol·min^–1·kg^–1); mean arterial pressure increased by an average of 2 kPa (15 mm Hg) and heart rate by 55 b/min; plasma renin activity fell from 0.37–0.21 ng Al·ml^–1·h^–1. Cardiac denervation eliminated these effects of left atrial distension except for a small increase in heart rate (12 b/min). This indicates that the natriuresis and diuresis during left atrial distension resulted from stimulation of receptors located in the left atrium.In contrast, during protocol 2 and 3, the same amounts of sodium and water were excreted in the cardiac denervated dogs as compared to the intact dogs. A comparable decrease in plasma renin activity also was observed. — Apparently the presence of the cardiac nerves is not a prerequisite for maintenance of sodium and water homeostasis.     

Retrograde HRP study of neurons in the cervical enlargement projecting to the cerebellum in the cat

Summary After cerebellar HRP injections in kittens labeled neurons were found in laminae V–VIII in the cervical enlargement. Most of the labeled neurons were localized in two groups, one in laminae V–VI, the other centrally in lamina VII. Labeled neurons were also observed in the medial part of lamina VII of C5 and T1 and a few in lamina VIII. Neurons in the cervical enlargement seem to terminate largely in cerebellar lobules IV–V of the anterior lobe. Some neurons in laminae V–VI terminated in the ipsilateral paramedian lobule. Neurons in laminae V–VI and central lamina VII of C5–T1 had uncrossed axons. Neurons in medial lamina VII of C5, in lamina VIII and neighbouring parts of lamina VII of C6–T1 had crossed axons. The ramifications of proximal dendrites and axons of the labeled neurons are described using the tetramethylbenzidine (TMB) method for HRP histochemistry. The neurons in the various laminae differed in their characteristic morphology. In conclusion, the findings of Matsushita et al. (1979) concerning the localization and axonal course of cerebellar projecting neurons in the cervical enlargement are confirmed. In addition new data concerning the morphology of the labeled neurons are presented.     

Character and frequency of pathological changes in the solitary rat kidney after removal of the other kidney in old age

One kidney was removed from male rats weighing 500–850 g; the remaining kidney underwent compensatory hypertrophy and, after 1–2 months, it was larger (index of hypertrophy 70–92%) in rats weighing 700–850 g than in animals weighing 500–600 g (56–58%). Histological investigation showed that this marked hypertrophy of the solitary kidney in old rats was not the result of disease of the organ, for pathological changes such as are sometimes found in intact and hypertrophied kidneys were found in only 38 of 223 animals. The results suggest that the ability of the kidneys to undergo, compensation and regeneration is not reduced in old age.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 9, pp. 362–366, September, 1977.     

Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney

In order to study the specificities of the contraluminal anion transport systems, the inhibitory potency of substituted benzene analogs on influx of [³H]PAH, [¹⁴C]succinate, and [³⁵S]sulfate from the interstitium into cortical tubular cells has been determined in situ: (1) Contraluminal [³H]PAH influx is moderately inhibited by benzene-carboxylate and benzene-sulfonate, and strongly by benzene-dicarboxylates,-disulfonates and carboxy-benzene-sulfonates, if the substituents are located at positions 1 and 3 or 1 and 4. The affinity of the PAH transporter to polysubstituted benzoates increases with increasing hydrophobicity, decreasing electron density at the carboxyl group and decreasing pK_a. Similar dependencies are observed for phenols. Benzaldehydes which do not carry an ionic negative charge are accepted by the PAH-transporter, if they possess a second partially charged aldehyde or NO₂-group. (2) Contraluminal [¹⁴C]succinate influx is inhibited by benzene 1,3- or 1,4-dicarboxylates,-disulfonates and 1,3-or 1,4-carboxybenzene-sulfonates. Monosubstituted benzoates do not interact with the dicarboxylate transporter, but NO₂-polysubstituted benzoates do. Phenol itself and 2-substituted phenol interact weakly possibly due to oligomer formation. (3) The contraluminal sulfate transporter interacts only with compounds which show a negative group accumulation such as 3,5-dinitro- or 3,5-dichloro-substituted salicylates. The data are consistent with three separate anion transport systems in the contraluminal membrane: The PAH transporter interacts with hydrophobic molecules carrying one or two negative charges (–COO^–, –SO ₃ ^– ) or two or more than two partial negative charges (–OH, –CHO, –SO₂NH₂, –NO₂). The dicarboxylate transporter requires two electronegative ionic charges (–COO^–, –SO ₃ ^– ) at 5–9 Å distance or one ionic and several partial charges (–Cl, –NO₂) at a favourable distance. The sulfate transporter interacts with molecules which have neighbouring electronegative charge accumulation.     

Termination profiles of photoreceptor cells in the larval eye of the swallowtail butterfly

Summary Profiles of the axonal endings of seven retinular cells (R1–7) from each of six stemmata (I–VI) of the butterflyPapilio xuthus were examined. Their axons enter the brain anteroventrally and project dorsally along the brain's lateral surface before entering the optic neuropil. Larval optic neuropil has two distinct areas, a (distal) lamina and a (proximal) medulla, connected by a chiasma. Intracellular administration of cobalt shows that distal retinular cells (R1–3 of stemmata I–IV, R1–3 and R6 of stemmata V and VI) terminate as short axons with plug or toothbrush-like endings in the lamina. Proximal retinular cells (R4–7 of stemmata I–IV, R4, R5 and R7 of stemmata V and VI) terminate as long axons in the chiasma or in the medulla. The long axons have fine branches in the lamina, chiasma and medulla. The two proximal cells (R5 and R7) are distinguished by their deeper endings and longer branches. The terminals of photoreceptors correspond to their photoreceptive properties and provide further evidence for the functional specialization of the photoreceptors.     

Effect of epitalon on the lifespan increase in Drosophila melanogaster

The geroprotector activity of epitalon, a synthetic tetrapeptide Ala–Glu–Asp–Gly, was studied on the Drosophila melanogaster wild strain Canton-S. The substance was added to the culture medium only at the developmental stage (from egg to larva). Epitalon significantly increased the lifespan (LS) of imagoes by 11–16% when applied at unprecedented low concentrations — from 0.001×10^–6 to 5×10^–6 wt.% of culture medium for males and from 0.01×10^–6 to 0.1×10^–6 wt.% of culture medium for females. The increase in LS did not depend on the substance dose. Effective concentrations of epitalon were 16 000–80 000 000 times lower than those of melatonin. The possible mechanisms of the antioxidant and regulatory effects of epitalon are discussed.     

Probing the roles of non-homologous insertions in the N-terminal domain of Plasmodium falciparum hydroxymethylpterin pyrophosphokinase–dihydropteroate synthase

Plasmodium falciparum bifunctional hydroxymethylpterin pyrophosphokinase–dihydropteroate synthase (pfHPPK–DHPS) is a crucial enzyme in the de novo folate biosynthesis pathway. The crystal structure is not yet available for this enzyme, however, homology model of the enzyme reported previously revealed the presence of parasite-specific insertions. Alignment of pfHPPK–DHPS with HPPK and DHPS sequences from other microorganisms reveals two insertions relative to the corresponding enzyme in other organisms, i.e. HPPK-1 and HPPK-2. The former encompasses amino acid residues 66–162, while the latter covers residues 213–311. In order to investigate the roles of the two insertions, we constructed a number of mutants in which parts of these two insertions were deleted. Characterization of the mutationally altered proteins revealed that deletions of residues 74–80 in the HPPK-1 sequence of the pfHPPK–DHPS, but not that of the monofunctional pfHPPK, decreased the HPPK activity. A longer deletion (residues 74–86) in the HPPK-1 sequence of the bifunctional pfHPPK–DHPS completely inactivated both HPPK and DHPS activities. However, deletion in the HPPK-2 sequence from residues 247–306 did not disrupt the activities of HPPK and DHPS, but the kinetic properties of the recombinant proteins were slightly changed. The importance of HPPK-1 sequence on the catalytic activities of HPPK and DHPS in the bifunctional pfHPPK–DHPS could have implications for development of inhibitors targeting the non-catalytic region of this chemotherapeutically important enzyme.     

Dynamics of Changes in Operant Reflexes in Rats after Transection of the Corticospinal Tract and Removal of the Sensorimotor Region of the Cerebral Cortex

Prior unilateral transection of the bulbar pyramid facilitated recovery of operant reflexes and compensatory processes occurring after removal of the ipsilateral sensorimotor cortex in rats. This increase in corticofugal plasticity was absent when only the sensorimotor cortex was removed. This phenomenon is explained by switching of descending influences to the corticorubrospinal system via the following loop: corticobulbar projection – red nucleus – lower olive – cerebellum – thalamus – cortex. A general property of this phenomenon is that prior lesioning of the peripheral part of the descending spinal projection acquires anticipatory signal value for mobilizing the compensatory abilities of the brain with the aim of recovering from the deficit of the central branch of the system.     

Risk Factors for the Development of Extended-Spectrum Beta-Lactamase-Producing Bacteria in Nonhospitalized Patients

Although the risk factors for acquiring infection by extended-spectrum beta-lactamase (ESBL)-producing bacteria have been investigated in hospitalized patients, such risk factors have not been defined in the community setting. In this study, clinical data from a total of 311 nonhospitalized patients with community-acquired urinary tract infection (128 with ESBL-positive strains and 183 with ESBL-negative strains) were obtained. According to a multivariate analysis, the following were identified as independent risk factors: previous hospitalization in the past 3 months (OR=8.95, 95%CI, 3.77–21.25), antibiotic treatment in the past 3 months (OR=3.23, 95%CI, 1.76–5.91), age over 60 years (OR=2.65, 95%CI, 1.45–4.83), diabetes (OR=2.57, 95%CI, 1.20–5.51), male gender (OR=2.47, 95%CI, 1.22–5.01), Klebsiella pneumoniae infection (OR=2.31, 95%CI, 1.17–4.54), previous use of third-generation cephalosporins (P=0.014, OR=15.8, 95%CI, 1.7–143), previous use of second-generation cephalosporins (P<0.0001, OR=10.1, 95%CI, 4.2–24), previous use of quinolones (P=0.001, OR=4.1, 95%CI, 1.8–9.0), and previous use of penicillin (P=0.003, OR=4.0, 95%CI, 1.6–9.0).     

Properties of the bursting Na channel in the presence of DPI 201-106 in guinea-pig ventricular myocytes

Single Na channel currents were measured in cellattached patches of guinea-pig ventricular myocytes in the presence of the S-enantiomer of DPI 201-106. DPI changes the kinetic pattern of channel activity from short living openings at the beginning of a depolarizing pulse (voltageindependent mean open time about 0.4 ms between –60 and –20 mV), into longlasting bursts of openings. The single channel current-voltage relation can be approximated by a straight line with a single channel conductance of 15 pS, which is the same as in the absence of DPI, and a reversal potential near the estimated Na equilibrium potential (+ 74 mV). The ensemble averaged Na current shows a fast peak of inward current, which partially decays within less than 10 ms, but which shows a large component which decays very slowly with a time constant of the order of 1s (1.31±0.6 s at –30 mV, 19 measurements in 12 cell-attached patches). The slowly decaying component activates with a half-maximum potential at –55.4±2.3 mV and a slope parameter s of 4.9±1.9 mV. The half-maximum potential of the steady-state inactivation is –115.6±1.8 mV, and the slope parameter is 9.1±1.5 mV. The open time distribution can be fitted by a single exponential only at potentials negative to –40 mV. The time constant is 1.3±0.14 ms at –50 mV (7 patches). At more positive potentials a slower second component is present (14.4±7.1 ms at –30mV, 7 patches), in addition to a fast component with a time constant between 2 and 3 ms (2.2±1.9 ms at –30 mV, 7 patches). The closed time distribution contains two exponential components. The time constant of the fast component decreases from about 1.3 ms at –70 mV to 0.3 ms at –20 mV (0.3±0.17 ms at –30 mV, 10 patches). The time constant of the second component decreases from about 4.0 ms at –70 mV to 1.5 ms at –20 mV (2.2±1.8 ms at –30 mV, 10 patches). At potentials positive to –50 mV also a small very slow component is present (8.8±5.6 ms at –30 mV). The contribution of the slow component to the closed time distribution increases for stronger depolarizations from 2.2±2.1% at –40 mV to 64±22% at –20 mV. The contribution of short closings to the total number of closings is increased from 51±4% at –70 mV to 83±12% at –20 mV. Openings occur clearly in bursts and the burst duration shows a very good correlation with the time constant of the decay of the ensemble average current in a large number of different experimental conditions. The channels are blocked by application of TTX. With 10 and 30 M TTX in the patch pipette (1 s pacing interval) the probability of the channel being open is decreased by about 90%. The long mean open time is significantly reduced when TTX is present in the patch pipette (5.7±2.6 ms at –30 mV with 5–30 M TTX, 4 patches,n=11). No significant differences are obtained for both closed times (_c1 = 0.26±0.07 ms, _c2 = 1.9±0.7 ms, 4 patches,n=9). The steady-state inactivation is not significantly changed in the presence of TTX (V_H=–112±2.9 mV, s=9.0±2.8 mV). The open state probability of the bursting Na channel is also reduced by more than 80% when 200 M Cd is present in the pipette solution (all mean ±SD).     

Extension of Rapid Phase-Contrast Magnetic Resonance Imaging Using BRISK in Multidirectional Flow

We developed BRISK–CON–VPS, a rapid phase-contrast cine approach that is a hybrid of the BRISK–VPS (Block Regional Interpolation Scheme for k-space) and conventional (CONV–VPS) scanning employing k-space views per segment (VPS). BRISK–CON–VPS allows data acquisition approximately four times faster than CONV–VPS imaging and has the advantage compared to BRISK–VPS that it can potentially be incorporated into real-time applications. In BRISK–CON–VPS contiguous regions of k-space are sampled using a views per segment factor that is varied as a function of distance from the k-space center. Computational fluid dynamics (CFD) data were used to simulate CONV–VPS, BRISK–VPS, and BRISK–CON–VPS. BRISK–CON–VPS was simulated by incrementing the VPS progressively with increasing distance from the k-space origin while BRISK–VPS was simulated using a uniform VPS applied to the sparse sampling scheme. Simulations showed that up to a base VPS of 5, both BRISK–CON–VPS and BRISK–VPS retained excellent axial-velocity accuracy. Secondary in-plane velocity flow fields were well represented with BRISK–CON–VPS and BRISK–VPS up to a base VPS of 3. CONV–VPS, BRISK–CON–VPS, and BRISK–VPS were applied in vivo and shown to provide comparable quantitative flow data. BRISK–CON–VPS accomplishes breath-hold acquisitions as efficiently as BRISK–VPS, but without requiring data interpolation or under-sampling k-space.     

Transport properties of the basolateral membrane of the oxyntic cells in frog fundic gastric mucosa

The conductive properties of the basolateral membrane of oxyntic cells (OC) of frog fundic gastric mucosa were investigated by utilizing the microelectrode technique. By examining the response of the basolateral cell membrane potential difference,V _cs, to sudden ion concentration changes in the serosal bath it was concluded that the basolateral membrane of OC has a high Ba²⁺-sensitive K⁺-conductance, and no Cl^–-conductance both in resting (cimetidine) and in stimulated (histamine) state. The response ofV _cs to serosal Cl^–-removal, consisting in a slight hyperpolarization (anomalous Nernst response), could not be explained by possible permeability changes to K⁺ and Na⁺ since the potential response to Cl^– was essentially preserved by blocking K⁺-permeability with Ba²⁺ and replacing all Na⁺ by choline. Conversely, hyperpolarization ofV _cs after Cl^–-free perfusion was abolished by exposure to HCO ₃ ^– -free solution, indicating that HCO ₃ ^– -ions are required at the serosal bath for Cl^– to get his effect. It was investigated wether the effect of Cl^– was due to an electrogenic Na⁺(HCO ₃ ^– ) _n /Cl^– exchange mechanism on the basolateral membrane. Experiments showed that the potential response to HCO ₃ ^– -removal and to Na⁺-removal, consisting in a depolarization ofV _cs, was similar both in presence and in absence of Cl^–. Furosemide (0.5 mmol/l) had no effect on steadyV _cs andV _t. The electrophysiological analysis of the data led to excluding the involvement of Na-Cl, Na-2Cl and NaK-2Cl cotransports, and to including the existence of an electrogenic Na⁺(HCO ₃ ^– ) _n /Cl^– exchange process, while suggests the presence of an electroneutral Cl^–/HCO ₃ ^– exchange mechanism to explain Cl^–-transport across the basolateral membrane of OC.This work was supported by a research grant from Ministero della Pubblica Istruzione, Rome, Italy     

Characteristics of excitation and inhibition in the receptive fields of the retina and lateral geniculate body

The process of excitation and inhibition in the receptive fields (RF) of the ganglion cells and lateral geniculate body (LGB) of the cat were examined. The extent of the dependence of the magnitude of excitation and inhibition in RF on stimulus intensity was determined. This dependence is a power function with power indices of 0.15–0.20 (LGB) and 0.3–0.5 (retina) for excitation and 0.2–0.3 (LGB) and 0.5–0.6 (retina) for inhibition.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 62, No. 3, pp. 368–374, March, 1976.     

Quantitative studies of intracellular postsynaptic potentials in the lateral geniculate nucleus of the cat with respect to optic tract stimulus response latencies

Summary LGN cells were intracellularly recorded with glass micropipettes. Electrical stimuli of different amplitude and frequency were applied to the optic tract close to the optic chiasm. The cells were classified according to stimulus response latencies of action potentials as belonging to class I (1.0–1.6 msec) or class II (1.7–3.0 msec).Class I EPSPs had shorter latencies (1.0–1.5 msec), durations (4–12 msec), rise times to peak (0.5–1.4 msec), and decay times (3.0–8.5 msec); the synaptic transmission time was on the average 0.41 msec. Class II EPSPs (1.6–2.6 msec latency) had longer durations (10–30 msec), rise times (1.6–3.7 msec), and decay times (9.0–25 msec); the synaptic transmission time was on the average 0.67 msec.With repetitive stimulation the EPSPs of latency class I revealed almost no stimulus frequency dependence between 1 and 120 Hz, while class II EPSPs decreased in amplitude between 30 and 70% with increasing frequency. Comparable temporal summation of excitation occurred in cells of both latency classes. Negative serial correlation coefficients of first order were found for consecutive EPSP amplitudes of all cells recorded for sufficient periods of time.The IPSPs were subdivided into two groups according to their optic tract response latency. Group 1 IPSPs had shorter latencies (2.0–2.6 msec), durations (15–50 msec), and times from the onset to maximal hyperpolarization (2.4–4.2 msec) than group 2 IPSPs (3.0–4.8 msec latency, 40–100 msec duration, 2.7–7.5 msec time from onset to extremum).The group 2 IPSPs decreased in amplitude by about 90% when the stimulus frequency was increased from 1 to 50 Hz, while the group 1 IPSPs displayed a comparable decrease in the frequency range between 50 and 120 Hz. Effective temporal summation was found in group 2 IPSPs in the frequency range below 70 Hz, and in group 1 IPSPs at stimulus frequencies between 70 and 120 Hz.The EPSP peak latencies and the latencies to the minimum of IPSPs proved to be invariant with respect to PSP amplitude and stimulus frequency in individual cells. The latencies to the extrema of EPSPs and IPSPs as well as the amplitude values were symmetrically distributed.     

Reflection of the level of alimentary motivation in the electrical activity of the esophageal muscles of the rabbit in the process of reinforcement

Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 40, No. 2, pp. 374–376, March–April, 1990.     

Role of 4-1BB in immune responses

4–1BB is an inducible T cell surface receptor which belongs to the tumor necrosis factor receptor superfamily, a group of cysteine–rich cell–surface molecules. Both human and mouse 4–1BB recently received HLDA nomenclature. Naive T cells lack 4–1BB, which is not only induced upon T cell activation, but also remains on activated T cells. The natural ligand for 4–1BB, 4–1BBL is also induced and is found on activated antigen–presenting cells. Cross–linking of the 4–1BB molecule by agonistic antibody transmits a distinct and potent co–stimulatory signal leading to the activation and differentiation of CD4⁺and CD8⁺cells. 4–1BB transmits signals through the TRAF2–NIK pathway and activates NF–κB. Signals relayed through 4–1BB inhibit activation–induced cell death and rescue the immune system during the post–CD28 phase. Antibodies to the 4–1BB molecule can increase GVHD, accelerate the rejection of cardiac allograft and skin transplants, and eradicate established tumors. Interference with the 4–1BB–4–1BBL pathway may be of therapeutic use in the treatment of HIV infection. 4–1BB–deficient mice show dysregulated immune responses and mount elevated Ig responses to T–dependent antigens.     

A chloride-bicarbonate exchanging anion carrier in vascular smooth muscle of the rabbit

Cl^– efflux into various incubation media (PSS) was studied in pieces of rabbit aortae loaded with³⁶Cl. Replacement of HCO ₃ ^– /CO₂ by HEPES/O₂ in the PSS increased the rate of Cl^– efflux by a factor of 2.4. This effect was suppressed in Cl^–-free PSS containing isethionate, propionate, or benzenesulfonate, but not in NO ₃ ^– -PSS, or Br^–-PSS. The stimulant effect of HCO ₃ ^– withdrawal on Cl^– efflux was reduced by 140 M DIDS, but not by 1 mM furosemide. The Cl^– effux was temperature-dependent (Q₁₀=2.3–2.5), and it was not affected on depolarisation by high [K⁺]₀. — The [Cl^–]_i of rabbit aorta determined by uptake studies with³⁶Cl, decreased slightly (by 15%) below controls in PSS containing 140 M DIDS, but drastically (from 32.6 to 13.5 mM, i.e. by 59%) in PSS containing 1 mM furosemide. — Withdrawal of HCO ₃ ^– /CO₂ depolarized rabbit pulmonary artery in standard PSS and in Br^–-PSS or NO ₃ ^– -PSS, but not in benzenesulfonate-PSS. — The pH_i of rabbit aorta determined by the distribution of (¹⁴C)-DMO, increased in Cl^–-free PSS containing isethionate or glucuronate. — It is concluded that transport mechanisms play a major role in the distribution of Cl^– in vascular smooth muscle, and that a membrane anion carrier operates in this tissue which can transport Cl^– and HCO ₃ ^– across the cell membrane. This mechanism seems to be involved in the regulation of pH_i. However, the known high [Cl^–]_i of vascular smooth muscle is rather mediated by the furosemide-sensitive Na–K–Cl cotransport than by this anion carrier.Supported by the Deutsche Forschungsgemeinschaft. Parts of this study have been reported to the German Physiological and Pharmacological Societies (Kreye and Gertheimer 1982; Kreye et al. 1984a, b), and at the First International Congress on Diuretics, Miami/USA (Kreye et al. 1984c)     

The role of the claustrum in the bilateral control of frontal oculomotor neurons in the cat

Summary The effect of claustrum (CL) stimulation on the spontaneous unitary activity of ipsi and contralateral frontal oculomotor neurons, was studied in chloralose-anaesthetized cats. A total of 205 units was bilaterally recorded in the medial oculomotor area, homologous of the primate frontal eye fields 127 neurons were identified as projecting to the superior colliculus; for 33 of these last units stimulation of the ipsilateral CL provoked an excitatory effect lasting 10–25 ms and appearing with a latency of 5–15 ms; on 8 units the excitatory effect was followed by an inhibition lasting 100–250 ms. Ninety-eight of the 127 neurons were also tested through activation of the contralateral CL: 13 cells showed an excitatory effect lasting 10–35 ms and appearing with a latency of 20–50 ms. In three of the thirteen units the excitatory effect was followed by an inhibition lasting 100–150 ms. Complete section of the corpus callosum abolished the contralateral CL effect, suggesting the existence of a direct claustro-contralateral oculomotor cortex pathway running through the corpus callosum. The results could support the hypothesis that the CL may play a role in the bilateral control of the visuomotor performance.