Sensitivity and transduction mechanisms of responses to general odorants in turtle vomeronasal system

(a) The responses of the vomeronasal organ to general odorants in the turtle, Geoclemys reevesii, were measured by recording the accessory olfactory bulbar responses. The threshold concentrations of the vomeronasal responses to various odorants were similar to those in main olfactory bulbar responses, indicating that vomeronasal cells lacking cilia and olfactory cells having many cilia have similar sensitivities to general odorants. (b) The vomeronasal epithelium was perfused with 100 mM NaCl solution and the salt-free solution and the effects of NaCl on the vomeronasal responses to various odorants were examined. There was no essential difference between the concentration-response curves for n-amyl acetate and menthone dissolved in 100 mM NaCl solution and those dissolved in the salt-free solution in the whole concentration range examined. The ratios of the magnitudes of vomeronasal responses in the salt-free solution to those in 100 mM NaCl solution were between 1.01 and 1.10 for seven odorants tested. (c) The magnitudes of responses to the odorants were unchanged by changes in NaCl concentrations. The replacement of Na+ with organic cations such as choline+, Bis-Tris propane2+, and N-acetyl-D-glucosamine+ did not affect the magnitudes of the responses to the odorants. The Na channel blocker amiloride also did not affect the responses. (d) The vomeronasal responses were practically unchanged by changes in CaCl2 concentration. The Ca channel blockers diltiazem and verapamil did not affect the responses. (e) The replacement of Cl- with SO4(2-) did not affect the magnitudes of the vomeronasal responses. (f) The present results suggest that ion transport across the apical membranes of vomeronasal receptor cells does not contribute to the responses to odorants in the turtle.     

Changes in blastogenic responses and antibody titers of mice infected with Toxoplasma gondii]

This study was performed to observe the cell-mediated and humoral immune responses in mice which were infected with Beverley, Fukaya and ME49 strain of Toxoplasma gondii, respectively. The blastogenic responses of splenocytes using [3H]-thymidine and serum antibody titers were measured weekly up to 10 weeks after infection. The blastogenic responses of splenocytes treated with concanavalin A and Toxoplasma lysate were significantly declined in the 3 strain groups as compared with the non-infected group (p less than 0.05), however lipopolysaccharide-treated blastogenic responses were not significantly different between infected and non-infected groups. The serum IgG antibody titers in the three infected groups increased from 2 weeks after infection, and the serum IgM antibody titers increased until 4 weeks after infection. No significant differences were revealed in blastogenic responses and serum antibody titers among the 3 groups. The present study suggested that cell-mediated immune responses were involved in T. gondii infected mice and blastogenic responses of T lymphocytes were inhibited in acute T. gondii infection.     

IgM-mediated enhancement of in vivo anti-sheep erythrocyte antibody responses: isotype analysis of the enhanced responses

The direct splenic anti-sheep erythrocyte (anti-SRBC) responses as well as the serum IgG1, IgG2a, IgG2b, and IgG3 anti-SRBC responses of CBA/CaJ mice were monitored 4-35 days after immunization with: (1) a suboptimal dose of SRBC, (2) a suboptimal dose of SRBC plus monoclonal IgM anti-SRBC, or (3) a high dose of SRBC. The direct plaque-forming cell (PFC) responses of mice in treatment group 2 were significantly higher than those in group 1 but similar to the responses in group 3. The serum anti-SRBC antibody responses of all IgG subclasses were significantly enhanced by IgM anti-SRBC and were generally even higher than the responses obtained with high doses of SRBC. The relative proportions of each serum IgG subclass were similar in all three groups. These data suggest that the enhancement of suboptimal anti-SRBC antibody responses by IgM anti-SRBC extends through IgM and all of the IgG subclasses and, further, that the isotype profile in antibody-enhanced responses is similar to that obtained with high doses of SRBC.     

Phase-dependent responses in locomotor muscles of walking man

Bilateral reflex responses in locomotor muscles were studied in normal human subjects walking on a treadmill. Reflex responses were elicited in response to a momentary resistance applied to one leg. The responses were recorded electromyographically from superficial muscles of both lower limbs: the vastus lateralis, gluteus medius and tibialis anterior. A four-channel storage oscilloscope displayed a quartet record which consisted of phases of the walking cycle and patterns of EMG activity. Resistance and response data were collected for comparison. The appearance of reflex responses was found to be conditioned. The following two observations provide the phase-dependent characteristics of those responses: muscles of the ipsilateral limb elicited responses throughout the walking cycle regardless of whether the muscles were active or silent and muscles of the contralateral limb produced responses that depended on the point at which resistance occurred during the walking cycle. Discusion follows concerning inhibition of the response that may be responsible for this phase-dependent phenomenon.     

The effects of anilidopiperidine analgesics on single respiratory and non-respiratory neurones in the brain stem of the rat

The effects of four anilidopiperidine analgesics, fentanyl, sufentanil, lofentanil and alfentanil on the activity of single neurones in the rat brain stem were examined using the technique of microiontophoresis. Neurones whose discharge rate could be related to respiration and non-respiratory neurones were studied. Alfentanil produced depression of neuronal firing which was slow in onset, shallow and prolonged, similar to the responses seen previously with etorphine. These responses were antagonised by naloxone. The depressant responses to fentanyl, sufentanil, and lofentanil were often different in character, being rapid in onset and of short duration, although slow long lasting responses also occurred and sometimes the two responses were combined. However, only the slow response was blocked by naloxone, the fast, short-duration response being naloxone-resistant. No differences in the responses of respiratory and non-respiratory neurones to these drugs were observed.     

初级视皮层神经元响应反应与撤反应的朝向选择性

朝向选择性是初级视皮层(17区或V1)神经元的基本性质,在图形感知中起着关键作用.同时这些神经元对于持续时间大于100 ms的视觉刺激具有清晰的响应反应(Onset responses)和撤反应(Offset responses).以往的研究只关注响应反应的朝向选择性,而忽视了对撤反应的朝向选择性研究.我们比较了响应与撤反应的朝向调谐性质,大多数细胞的撤反应与响应反应基本上具有相似的最优朝向,而撤反应的朝向调谐宽度有窄于响应反应的趋势,撤反应的最优延迟普遍滞后于响应反应的最优延迟.撤反应的朝向选择性略强于响应反应和具有显著长的反应延迟提示,皮层内的反馈输入可能在形成撤反应的朝向选择性中起着作用.本研究揭示了撤反应的朝向选择性在刺激朝向的连续表征和主体在形状知觉的后期对朝向的精细区分中起着作用.     

Amiloride-sensitive and amiloride-insensitive responses to NaCl + acid mixtures in hamster chorda tympani nerve

Component signaling in taste mixtures containing both beneficial and dangerous chemicals depends on peripheral processing. Unidirectional mixture suppression of chorda tympani (CT) nerve responses to sucrose by quinine and acid is documented for golden hamsters (Mesocricetus auratus). To investigate mixtures of NaCl and acids, we recorded multifiber responses to 50 mM NaCl, 1 and 3 mM citric acid and acetic acid, 250 μM citric acid, 20 mM acetic acid, and all binary combinations of each acid with NaCl (with and without 30 μM amiloride added). By blocking epithelial Na(+) channels, amiloride treatment separated amiloride-sensitive NaCl-specific responses from amiloride-insensitive electrolyte-generalist responses, which encompass all of the CT response to the acids as well as responses to NaCl. Like CT sucrose responses, the amiloride-sensitive NaCl responses were suppressed by as much as 50% by citric acid (P = 0.001). The amiloride-insensitive electrolyte-generalist responses to NaCl + acid mixtures approximated the sum of NaCl and acid component responses. Thus, although NaCl-specific responses to NaCl were weakened in NaCl-acid mixtures, electrolyte-generalist responses to acid and NaCl, which tastes KCl-like, were transmitted undiminished in intensity to the central nervous system. The 2 distinct CT pathways are consistent with known rodent behavioral discriminations.     

Characterization of thromboxane receptor blocking effects of SQ 29548 in the feline pulmonary vascular bed.

The effects of SQ 29548, a thromboxane (Tx) A2 receptor blocking agent, on responses to the TxA2 mimic U46619 were investigated in the pulmonary vascular bed of the intact-chest cat under constant-flow conditions. The administration of SQ 29548 in doses of 0.25-1 mg/kg iv reduced vasoconstrictor responses to U-46619; however, responses to prostaglandins (PG) F2 alpha and D2 and to serotonin were also decreased. After administration of SQ 29548 in doses of 0.05-0.1 mg/kg iv, responses to U-46619 and U-44069 were reduced significantly, and the dose-response curves for these TxA2 mimics were shifted to the right in a parallel manner at a time when responses to PGF2 alpha and PGD2 were not altered. The low doses of the TxA2 receptor blocking agent significantly reduced responses to the PG and TxA2 precursor arachidonic acid but were without significant effect on vasoconstrictor responses to serotonin; histamine; norepinephrine; angiotensin II; the major PGD2 metabolite 9 alpha,11 beta-PGF2; BAY K 8644, an agent that enhances calcium entry; and endothelin-1. The present data show that at low doses SQ 29548 selectively blocks TxA2 receptor-mediated responses in a competitive and reversible manner in the pulmonary vascular bed. These data suggest that responses to arachidonic acid are mediated in large part by the formation of TxA2 and provide evidence in support of the hypothesis that a discrete TxA2 receptor unrelated to PGF2 alpha or PGD2 receptors is present in undefined resistance vessel elements in the feline pulmonary vascular bed.     

HIV-induced immunodeficiency. Relatively preserved phytohemagglutinin as opposed to decreased pokeweed mitogen responses may be due to possibly preserved responses via CD2/phytohemagglutinin pathway

We studied the proliferative response of PBL to the mitogens PHA and PWM and Candida albicans Ag in 301 HIV seropositive homosexual men, of whom 55 had AIDS. The responses to PHA were reduced only in the clinically ill HIV seropositive subjects. In contrast, the responses to PWM were profoundly reduced in most HIV seropositive subjects including the asymptomatic group. Further analysis of 16 HIV seropositive subjects showed that the proliferative responses were reduced in both CD4 and CD8 T cell subsets. A total of 15 HIV seropositive individuals with low responses to PWM, of whom seven had AIDS and eight controls were chosen for the following studies. Expression of T3, Ti, delta receptors, and CD2 was investigated and showed an increased percentage of CD2 receptors positive cells in HIV seropositive subjects without AIDS. The proliferative responses of PBL to stimulation with PHA, PWM, antibodies to CD3, or antibodies to CD2 were investigated and showed significant correlation in controls, whereas in contrast, only the responses to PHA and CD2ab correlated in patients with AIDS. The proliferative responses to CD2ab and CD3ab in controls were larger than the responses to both PHA and PWM. In patients, these responses were less suppressed than the responses to PWM indicating that stimulation with mitogens is more complex than a simple stimulation of Ti/T3 and CD2 receptors. Further investigations were done on resting T cells, i.e., lymphocytes depleted of macrophages and pre-activated cells. Addition of PHA to these cells resulted in preactivation with expression of IL-2R (CD25) but not in proliferation. In contrast, addition of PHA plus SRBC, which bind to the CD2 receptors caused IL-2R expression, IL-2 production, and proliferation. Addition of PWM + SRBC did not result in proliferation. A comparison of the responses to PHA + SRBC of resting T cells from 26 HIV seropositive individuals, of whom seven had AIDS and 12 seronegative controls, showed that these responses were normal or only slightly decreased in the 19 seropositive men without AIDS whereas it was decreased in AIDS patients. Nevertheless, all AIDS patients showed clear-cut responses in this assay. Thus, the discrepancy between responses to PHA and PWM may be explained by an at least partially preserved function of the PHA/CD2-dependent pathway. We suggest that the defect induced by the HIV infection primarily concerns T3/Ti-induced responses.     

Identification of a respiratory related area in the rat insular cortex

The aim of this study was to map areas within the rat insular cortex from which respiratory responses originate and compare those sites with gastrointestinal control regions. The insular cortex was systematically microstimulated and histological location of responsive sites determined. Increased inspiratory airflow and decreased respiratory cycle duration were considered to be respiratory excitatory responses. The responses were localized in dysgranular and agranular insular cortex at levels caudal to the joining of the anterior commissure. More rostrally, respiratory inhibitory responses were elicited: these were manifested as a decrease in inspiratory airflow without a significant alteration in respiratory cycle duration. Respiratory inhibitory responses were usually accompanied by changes in gastric motility. These results suggest that the respiratory area in the rat insular cortex consist of two distinct zones which overlap a region modulating the gastrointestinal activity.     

Nonlinear Transient Responses from Light-Adapted Wolf Spider Eyes to Changes in Background Illumination

Retinal action potentials were recorded at the corneas of light-adapted wolf spider eyes in response to large positive and negative step changes in background illumination. These incremental responses were superimposed upon the steady-state DC responses to the background illumination. Both positive and negative step responses had peaks which overshot the DC levels to which they decayed. The overshoot was greater for positive than for negative steps. Short term DC responses measured after one-half sec were larger for negative than for positive steps; these short-term DC responses were thus asymmetrical. However, responses to short positive and negative flashes were not asymmetrical; rather, they varied linearly with flash amplitude. Asymmetries were thus delayed in onset. The short-term DC responses were found to be different from the steady-state DC responses to maintained changes in background illumination. There was an approximately exponential decay or creep from the short-term to the steady-state DC responses. It is proposed that the dynamics of delayed asymmetries can explain the waveforms of the short-term transient responses.     

Melanophores of Zacco temmincki (Teleostei) are light sensitive

The responses of melanophores of a cyprinid fish Zacco temmincki to changes in illumination were examined in isolated scale preparations of the adult fishes. Melanosomes in the melanophores aggregated in darkness and dispersed in light. These responses were invariably induced, even in denervated melanophores. These light responses, the dark-induced aggregation and the light-induced dispersion, were not affected by a number of alpha and beta adrenergic blocking agents. It was concluded that the melanophores of Zacco temmincki were themselves light sensitive and responded directly to light by melanosome translocations. The light responses were quantitatively assessed in relation to the intensity of illumination.     

Immunity to Plasmodium berghei yoelii in mice. II. Specific and nonspecific cellular and humoral responses during the course of infection.

The kinetics of various specific and nonspecific immunologic responses were examined in BALB/c mice infected with 17X nonlethal Plasmodium berghei yoelii (a self-limiting infection). The sequence of events after infection was characterized by rapid sensitization of splenic T cells to malaria antigen and polyclonal B cell activation, followed by a period of depressed splenic proliferative responses in vitro to mitogens (PHA and LPS) and malaria (specific) antigen. At the same time, suppressed primary in vitro splenic PFC responses to trinitrophenyl-aminoethylcarbamylmethyl-Ficoll (TNP-F) were seen. This suppression was an active process requiring adherent cells. During this period, levels of antimalarial antibody also increased exponentially. As the infection was cleared, splenic malaria antigen-specific proliferative responses were again observed and splenic PFC and in vitro mitogen responses returned to preinfection levels after variable periods of time. Both splenic proliferative responses to malaria antigen and antimalarial antibody responses remained persistently elevated. In addition, some responses were examined in mice infected with 17X lethal P.b. yoelii (a fatal infection); in comparison to the early responses of mice infected with the nonlethal substrain, there was a decrease and delay in the development of a splenic T cell response to malaria antigen and a blunted antimalarial antibody response.     

Synaptic reactions of sensomotor cortex neurons to stimulation of emotionally significant brain structures

The study deals with synaptic and spike responses of neurones in the rat sensorimotor cortex to stimulation of the lateral and medial hypothalamus, locus coeruleus and raphe nuclei. The activity of 57 neurones was recorded, 41 of them intracellularly and quasi-intracellularly, in response to the stimulation of sites in these structures, which were previously identified as "emotionally/ significant. No considerable differences in the effects of the stimulation of different "emotiogenic" zones were found. The stimulation parameters, differing from the "behavioural" ones by a greater strength, elicited in the majority of neurones clear post-synaptic responses, often in the form of EPSP-IPSP. Latencies of the responses varied from 3 to 80 msec. The most stable and pronounced responses were obtained to the stimulation of the lateral hypothalamus. No significant correlations of the latencies of the responses to the stimulation of different "emotiogenic" structures were found.     

Chemosensitivity of single smooth muscle cells to acetylcholine, noradrenaline, and histamine in vitro

Electrical responses to acetylcholine, noradrenaline, and histamine were recorded from solitary smooth muscle cells. Iontophoresis of each transmitter elicited three fast responses: a hyperpolarization, a depolarization, or a biphasic hyperpolarization-depolarization. Each transmitter activated a specific receptor since responses were specifically blocked by antagonists, two transmitters elicited different responses in solitary cells, and desensitization of response to one transmitter did not cause desensitization of responses to other transmitters. Responses were due to increased ion conductances since input resistance decreased during responses and reversal potentials were measured for depolarizing responses (-5 mV) and hyperpolarizing responses (-60 mV). Regional differences in transmitter sensitivity were mapped on solitary cells. Biphasic responses were due to simultaneous activation of receptors mediating hyperpolarizing responses and receptors mediating depolarizing responses which were segregated in the cell membrane. Noradrenaline enhanced action potential amplitude by regulation of voltage-dependent ion conductances. Finally, noradrenaline and histamine elicited periodic hyperpolarizing potentials, which may be due to increased intracellular Ca++.     

Differences in HIV-specific T cell responses between HIV-exposed and -unexposed HIV-seronegative individuals

HIV-1-specific T lymphocyte responses in individuals exposed to HIV-1 but who remain persistently seronegative (HESNs) have been reported in some but not all previous studies. This study was designed to resolve unequivocally the question of whether HESNs make HIV-1-specific T cell responses. We performed a blind investigation to measure HIV-1-specific T cell responses in both HIV-1-serodiscordant couples and HIV-1-unexposed seronegative controls (HUSNs). We found low-frequency HIV-1-specific T cells in both HESNs and HUSNs but show that the response rates were higher over time in the former (P = 0.01). Furthermore, the magnitudes of the HIV-1-specific T cell responses were significantly higher among responding HESNs than among HUSNs over time (P = 0.002). In both groups, responses were mediated by CD4 T cells. The responses were mapped to single peptides, which often corresponded to epitopes restricted by multiple HLA-DR types that have previously been detected in HIV-1-infected patients. HIV-1-specific T cell responses in HUSNs and some HESNs likely represent cross-reactivity to self or foreign non-HIV-1 antigens. The significantly greater T cell responses in HESNs, including in two who were homozygous for CCR5Δ32, demonstrates that HIV-1-specific T cell responses can be induced or augmented by exposure to HIV-1 without infection.     

Cellular requirements for induction of human primary proliferative responses to trinitrophenyl-modified cells

Cellular requirements for induction of primary proliferative responses by human T cells to trinitrophenylated autologous stimulators have been characterized. Substantial proliferative responses were observed with each of the Ia+ stimulator populations tested. Nevertheless, major differences in the hapten specificity of such responses were observed. Thus purified macrophages/monocytes (M phi) when TNP-modified induced responses that were relatively modest in absolute magnitude, but were highly hapten specific. This reflected the very limited capacity of purified M phi to induce proliferation when unmodified, i.e., an autologous mixed leukocyte response (AMLR). In contrast, unmodified M phi-depleted B plus null cells were potent stimulators of AMLR, but hapten modification did not significantly enhance the responses induced by these cells. Moreover, when M phi were added to B plus null cell stimulators AMLR responses were reduced and, with TNP-modified stimulators, hapten-specific responses were restored. The data thus suggest that M phi may have important roles in induction of primary T cell responses to conventional antigens but function largely as regulators rather than stimulators of AMLR. Finally, we have introduced a novel antigen-presenting cell population, the irradiated Ia+ TNP-specific cloned T cell. The possibility that such cells may utilize autostimulatory positive feedback circuits for activation of naive T cells and in interactions between subpopulations of hapten-reactive T cells is discussed.     

Electrophysiological responses of female Helicoverpa armigera (Hübner) (Lepidoptera; Noctuidae) to synthetic host odours

Studies were conducted to investigate the electroantennographic (EAG) responses of adult female Helicoverpa armigera to a range of known and putative kairomone components. The studies show that at a given dose the EAG responses elicited by a series of straight-chain aliphatic primary alcohols were not dependent on volatility since butan-1-ol and pentan-1-ol elicited EAG responses that were significantly smaller than those elicited by hexan-1-ol. The amplitudes of responses to hexan-1-ol were found to be dose dependent with a dose of 10(-1) μmol at source in a non-volatile solvent eliciting the largest response. Similarly, changes in functionality in a range of C(6) straight-chain aliphatic compounds significantly changed the amplitude of response elicited, with aldehydes eliciting smaller responses than the related primary alcohols and saturated compounds eliciting higher responses than related unsaturated compounds. Of the range of nine host plant-produced terpenoids tested, ocimene and beta-phellandrene elicited the highest responses and of the six aromatic compounds tested phenylacetaldehyde and benzaldehyde elicited the largest responses, at the doses tested. The significance of these findings for analysis of floral odours by gas chromatography linked to electroantennography as a means of identifying kairomone components attractive to H. armigera are discussed.     

A functional map in rat olfactory epithelium

Multiple (four or eight) electrode arrays were placed for simultaneous electro-olfactogram (EOG) recordings of responses to a series of odors applied directly to the olfactory epithelium. Three different surfaces of the epithelium were exposed in rats immediately after death by anesthetic overdose. We tested three terpene compounds (carvone, limonene and 1,8-cineole) across the epithelium along the medial surface of the endoturbinate bones. Carvone, a ketone, evoked larger responses dorsally on the epithelium. The largest responses to 1,8-cineole (an ether) were seen in an intermediate-ventral region. The responses to limonene (a hydrocarbon) did not vary greatly across the regions, although they were often larger ventrally. The response distributions deviated from this simple pattern on the caudal part of endoturbinate IV, where the carvone responses were small and the limonene responses were larger. These differences were evident across a substantial concentration range. Similar distributions were seen for these three odors in tests along the dorsal-to-ventral direction across the nasal septum and in the medial-to-lateral direction across the dorsal aspect of one of the endoturbinate bones reaching out into the lateral recess. We argue that the spatial distributions of responses are correlated with the olfactory receptor gene expression zones.     

Anti-IgD enhancement of primary antibody responses in rats

The role of membrane IgD in immune responses was examined by treating adult rats with anti-IgD. Anti-IgD when administered to rats in conjunction with optimal or suboptimal doses of either SRBC, a T-dependent antigen, or DNP-Ficoll, a T-independent antigen, enhanced the antibody responses. The greatest enhancement was obtained when anti-IgD was administered before the antigen. The effects of anti-IgD on antibody responses to SRBC were: (i) significant antibody responses to suboptimal antigen concentrations; (ii) greater antibody responses to optimal antigen concentrations; (iii) accelerated antibody responses; (iv) an early shift from IgM to IgG antibodies; (v) prolonged antibody responses. Similar effects on the immune response to DNP-Ficoll were observed with the exception that all antibodies were 2ME sensitive (IgM). These results suggest that an anamnestic type of immune response can be induced in anti-IgD-treated rats when given a primary antigen exposure. Injection of anti-IgD without SRBC or DNP-Ficoll induces B-cell proliferation without detectable antibody production to these antigens, indicating at least two signals are required for the enhanced antibody responses.