Maternal high-fat diet during lactation reprograms the dopaminergic circuitry in mice.

The maternal perinatal environment modulates brain formation, and altered maternal nutrition has been linked to the development of metabolic and psychiatric disorders in the offspring. Here, we showed that maternal high-fat diet (HFD) feeding during lactation in mice elicits long-lasting changes in gene expression in the offspring's dopaminergic circuitry. This translated into silencing of dopaminergic midbrain neurons, reduced connectivity to their downstream targets, and reduced stimulus-evoked dopamine (DA) release in the striatum. Despite the attenuated activity of DA midbrain neurons, offspring from mothers exposed to HFD feeding exhibited a sexually dimorphic expression of DA-related phenotypes, i.e., hyperlocomotion in males and increased intake of palatable food and sucrose in females. These phenotypes arose from concomitantly increased spontaneous activity of D1 medium spiny neurons (MSNs) and profoundly decreased D2 MSN projections. Overall, we have unraveled a fundamental restructuring of dopaminergic circuitries upon time-restricted altered maternal nutrition to induce persistent behavioral changes in the offspring.

Plateau potentials in developing antennal-lobe neurons of the moth, Manduca sexta.

Using whole cell recordings from antennal-lobe (AL) neurons in vitro and in situ, in semi-intact brain preparations, we examined membrane properties that contribute to electrical activity exhibited by developing neurons in primary olfactory centers of the brain of the sphinx moth, Manduca sexta. This activity is characterized by prolonged periods of membrane depolarization that resemble plateau potentials. The presence of plateau potential-generating mechanisms was confirmed using a series of tests established earlier. Brief depolarizing current pulses could be used to trigger a plateau state. Once triggered, plateau potentials could be terminated by brief pulses of hyperpolarizing current. Both triggering and terminating of firing states were threshold phenomena, and both conditions resulted in all-or-none responses. Rebound excitation from prolonged hyperpolarizing pulses could also be used to generate plateau potentials in some cells. These neurons were found to express a hyperpolarization-activated inward current. Neither the generation nor the maintenance of plateau potentials was affected by removal of Na+ ions from the extracellular medium or by blockade of Na+ currents with TTX. However, blocking of Ca2+ currents with Cd2+ (5 x 10(-4) M) inhibited the generation of plateau potentials, indicating that, in Manduca AL neurons, plateau potentials depend on Ca2+. Examining Ca2+ currents in isolation revealed that activation of these currents occurs in the absence of experimentally applied depolarizing stimuli. Our results suggest that this activity underlies the generation of plateau potentials and characteristic bursts of electrical activity in developing AL neurons of M. sexta.

Long-term maintenance of channel distribution in a central pattern generator neuron by neuromodulatory inputs revealed by decentralization in organ culture.

Organotypic cultures of the lobster (Homarus gammarus) stomatogastric nervous system (STNS) were used to assess changes in membrane properties of neurons of the pyloric motor pattern-generating network in the long-term absence of neuromodulatory inputs to the stomatogastric ganglion (STG). Specifically, we investigated decentralization-induced changes in the distribution and density of the transient outward current, I(A), which is encoded within the STG by the shal gene and plays an important role in shaping rhythmic bursting of pyloric neurons. Using an antibody against lobster shal K(+) channels, we found shal immunoreactivity in the membranes of neuritic processes, but not somata, of STG neurons in 5 d cultured STNS with intact modulatory inputs. However, in 5 d decentralized STG, shal immunoreactivity was still seen in primary neurites but was likewise present in a subset of STG somata. Among the neurons displaying this altered shal localization was the pyloric dilator (PD) neuron, which remained rhythmically active in 5 d decentralized STG. Two-electrode voltage clamp was used to compare I(A) in synaptically isolated PD neurons in long-term decentralized STG and nondecentralized controls. Although the voltage dependence and kinetics of I(A) changed little with decentralization, the maximal conductance of I(A) in PD neurons increased by 43.4%. This increase was consistent with the decentralization-induced increase in shal protein expression, indicating an alteration in the density and distribution of functional A-channels. Our results suggest that, in addition to the short-term regulation of network function, modulatory inputs may also play a role, either directly or indirectly, in controlling channel number and distribution, thereby maintaining the biophysical character of neuronal targets on a long-term basis.

Parallel organization in honey bee mushroom bodies by peptidergic Kenyon cells.

Antisera against the neuromodulatory peptides, Phe-Met-Arg-Phe-NH(2)-amide (FMRFamide) and gastrin cholecystokinin, demonstrate that the mushroom bodies of honey bees are subdivided longitudinally into strata. Three-dimensional reconstructions demonstrate that these strata project in parallel through the entire pedunculus and through the medial and vertical lobes. Immunostaining reveals clusters of immunoreactive cell bodies within the calyx cups and immunoreactive bundles of axons that line the inside of the calyx cup and lead to strata. Together, these features reveal that immunoreactive strata are composed of Kenyon cell axons rather than extrinsic elements, as suggested previously by some authors. Sorting amongst Kenyon cell axons into their appropriate strata already begins in the calyx before these axons enter the pedunculus. The three main concentric divisions of each calyx (the lip, collar, and basal ring) are divided further into immunoreactive and immunonegative zones. The lip neuropil is divided into two discrete zones, the collar neuropil is divided into five zones, and the basal ring neuropil is divided into four zones. Earlier studies proposed that the lip, collar, and basal ring are represented by three broad bands in the lobes: axons from adjacent Kenyon cell dendrites in the calyces are adjacent in the lobes even after their polar arrangements in the calyces have been transformed to rectilinear arrangements in the lobes. The universality of this arrangement is not supported by the present results. Although immunoreactive zones are found in all three calycal regions, immunoreactive strata in the lobes occur mainly in the two bands that were ascribed previously to the collar and the basal ring. In the lobes, immunoreactive strata are visited by the dendrites of efferent neurons that carry information from the mushroom bodies to other parts of the brain. Morphologically and chemically distinct subdivisions through the pedunculus and lobes of honey bees are comparable to longitudinal subdivisions demonstrated in the mushroom bodies of other insects, such as the cockroach Periplaneta americana. The functional and evolutionary significance of the results is discussed.

5-Hydroxy-tryptamine modulates pheromone-evoked local field potentials in the macroglomerular complex of the sphinx moth Manduca sexta.

Extra- and intracellular recordings from an intact brain preparation were used to study the effects of 5-hydroxytryptamine (5-HT or serotonin) on projection neurons in the sexually dimorphic macroglomerular complex (MGC) in the antennal lobe of the male moth Manduca sexta. The MGC is a group of three identified glomeruli specialized for synaptic processing of primary afferent information about the multi-component sex pheromone of the female. We investigated the modulatory effects of 5-HT on pheromone-evoked local field potentials in the MGC. The magnitude and duration of these potentials, which are thought to be generated by a population of pheromone-sensitive projection neurons of the MGC, were increased by 5-HT. Using intracellular recordings from the neurites of individual MGC projection neurons, we found that 5-HT increased the number of action potentials in response to pheromonal stimulation. These findings correlate well with earlier experiments that used other recording techniques. Our results are further evidence that 5-HT modulates a population of pheromone-sensitive MGC projection neurons that relay information about the pheromonal stimulus from the MGC to higher-order centers in the protocerebrum and are therefore pivotal for mate-finding and odor-guided behavior.

Highly localized Ca(2+) accumulation revealed by multiphoton microscopy in an identified motoneuron and its modulation by dopamine.

Calcium is essential for synaptic transmission and the control of the intrinsic firing properties of neurons; this makes Ca(2+) channels a prime target for neuromodulators. A combination of multiphoton microscopy and voltage-clamp recording was used to determine the localization of voltage-dependent Ca(2+) accumulation in the two pyloric dilator (PD) neurons of the pyloric network in the spiny lobster, Panulirus interruptus, and its modulation by dopamine. We monitored [Ca(2+)](i) in fine distal branches in the neuropil >350 microm below the surface of the ganglion during controlled voltage steps in voltage clamp. Ca(2+) accumulation originated mostly from small, fairly rare, spatially restricted varicosities on distal neuritic arborizations. Ca(2+) diffused from these point sources into adjacent regions. Varicosities with similar morphology in the PD neuron have been shown previously to be sites of synaptic contacts. We have demonstrated in earlier studies that dopamine inhibits activity and greatly reduces synaptic transmission from the PD neuron. In approximately 60% of the varicosities, the voltage-activated Ca(2+) accumulation was reduced by exogenous dopamine (DA) (10(-4) M). DA decreased the peak amplitude of Ca(2+) accumulation but had no effect on the rise and decay time. We conclude that DA reduces chemical synaptic transmission from the PD neurons at least in part by decreasing Ca(2+) entry at neurotransmitter release sites.

Serotonin enhances central olfactory neuron responses to female sex pheromone in the male sphinx moth manduca sexta.

In the brain of the sphinx moth Manduca sexta, sex-pheromonal information is processed in a prominent male-specific area of the antennal lobe called the macroglomerular complex (MGC). Whole-cell patch-clamp recordings from identified projection (output) neurons in the MGC have shown that serotonin [5-hydroxytryptamine (5-HT)] increases both the excitability of MGC projection neurons and their responses to stimulation with pheromone. At least two types of voltage-activated potassium currents in these cells are modulated by 5-HT. 5-HT decreases the maximal conductance of a transient potassium current (I(A)) and shifts its voltage for half-maximal inactivation to more negative potentials without affecting the half-maximal voltage for activation. This reduces the "window current" between the voltage activation and inactivation curves, decreasing the tonically active I(A) near the resting potential and causing the cell to depolarize. 5-HT's effect in this case is to decrease both the transient and resting K(+) conductance by modulating the same channel (I(A)). 5-HT also decreases the maximal conductance of a sustained potassium current [I(K(V))] without affecting its voltage dependence. Using HPLC, we show also that levels of 5-HT in the antennal lobes fluctuate significantly over a 24 hr period. Interestingly, 5-HT levels are highest at times when the moths are most active. We suggest that by controlling the responsiveness of antennal-lobe projection neurons to olfactory stimuli, 5-HT will have significant impact on the performance of odor-dependent behaviors.

Dopamine modulates two potassium currents and inhibits the intrinsic firing properties of an identified motor neuron in a central pattern generator network.

The two pyloric dilator (PD) neurons are components [along with the anterior burster (AB) neuron] of the pacemaker group of the pyloric network in the stomatogastric ganglion of the spiny lobster Panulirus interruptus. Dopamine (DA) modifies the motor pattern generated by the pyloric network, in part by exciting or inhibiting different neurons. DA inhibits the PD neuron by hyperpolarizing it and reducing its rate of firing action potentials, which leads to a phase delay of PD relative to the electrically coupled AB and a reduction in the pyloric cycle frequency. In synaptically isolated PD neurons, DA slows the rate of recovery to spike after hyperpolarization. The latency from a hyperpolarizing prestep to the first action potential is increased, and the action potential frequency as well as the total number of action potentials are decreased. When a brief (1 s) puff of DA is applied to a synaptically isolated, voltage-clamped PD neuron, a small voltage-dependent outward current is evoked, accompanied by an increase in membrane conductance. These responses are occluded by the combined presence of the potassium channel blockers 4-aminopyridine and tetraethylammonium. In voltage-clamped PD neurons, DA enhances the maximal conductance of a voltage-sensitive transient potassium current (IA) and shifts its Vact to more negative potentials without affecting its Vinact. This enlarges the "window current" between the voltage activation and inactivation curves, increasing the tonically active IA near the resting potential and causing the cell to hyperpolarize. Thus DA's effect is to enhance both the transient and resting K+ currents by modulating the same channels. In addition, DA enhances the amplitude of a calcium-dependent potassium current (IO(Ca)), but has no effect on a sustained potassium current (IK(V)). These results suggest that DA hyperpolarizes and phase delays the activity of the PD neurons at least in part by modulating their intrinsic postinhibitory recovery properties. This modulation appears to be mediated in part by an increase of IA and IO(Ca). IA appears to be a common target of DA action in the pyloric network, but it can be enhanced or decreased in different ways by DA in different neurons.

Voltage-activated currents from adult honeybee (Apis mellifera) antennal motor neurons recorded in vitro and in situ.

Voltage-activated currents from adult honey bee antennal motor neurons were characterized with in vitro studies in parallel with recordings taken from cells in situ. Two methods were used to ensure unequivocal identification of cells as antennal motor neurons: 1) selective backfilling of the neurons with fluorescent markers before dissociation for cell culture or before recording from cells in intact brains, semiintact brains, or in brain slices or 2) staining with a fluorescent marker via the patch pipette during recordings and identifying antennal motor neurons in situ on the basis of their characteristic morphology. Four voltage-activated currents were isolated in these antennal motor neurons with pharmacological, voltage, and ion substitution protocols. The neurons expressed at least two distinct K+ currents, a transient current (IA) that was blocked by 4-aminopyridine (4-5 x 10(-3) M), and a sustained current (IK(V)) that was partially blocked by tetraethylammonium (2-3 x 10(-2) M) and quinidine (5 x 10(-5) M). IA activated above -40 to -30 mV and the half-maximal voltages for steady-state activation and inactivation were -8.8 and -43.2 mV, respectively. IK(V) activated above -50 to -40 mV and the midpoint of the steady-state activation curve was +11.2 mV. IK(V) did not show steady-state inactivation. Additionally, two inward currents were isolated: a tetrodotoxin (10(-7) M)-sensitive, transient Na+ current (INa) that activated above -35 mV, with a maximum around -5 mV and a half-maximal voltage for inactivation of -72.6 mV, and a CdCl2 (5 x 10(-5) M)-sensitive Ca2+ current that activated above -45 to -40 mV, with a maximum around -15 mV. This study represents the first step in our effort to analyze the cellular and ionic mechanisms underlying the intrinsic properties and plasticity of antennal motor neurons.

Voltage-activated currents in identified giant interneurons isolated from adult crickets gryllus bimaculatus

The electrophysiological properties of cultured giant interneurons isolated from the terminal ganglion of adult crickets (Gryllus bimaculatus) were investigated using whole-cell patch-clamp techniques. To allow for unequivocal identification of these interneurons in cell culture, a protocol for fast and selective labeling of their cell bodies was established. Prior to cell dissociation, the giant interneurons were backfilled through their axons in situ with a fluorescent dye (dextran tetramethylrhodamine). In primary cell cultures, the cell bodies of giant interneurons were identified among a population of co-cultured neurons by their red fluorescence. Action potentials were recorded from the cell bodies of the cultured interneurons suggesting that several types of voltage-activated ion channels exist in these cells. Using voltage-clamp recording techniques, four voltage-activated currents were isolated and characterized. The giant interneurons express at least two distinct K+ currents: a transient current that is blocked by 4-aminopyridine (4x10(-3 )mol l-1) and a sustained current that is partially blocked by tetraethylammonium (3x10(-2 )mol l-1) and quinidine (2x10(-4 )mol l-1). In addition, a transient Na+ current sensitive to 10(-7 )mol l-1 tetrodotoxin and a Ca2+ current blocked by 5x10(-4 )mol l-1 CdCl2 have been characterized. This study represents the first step in an attempt to analyze the cellular and ionic mechanisms underlying plasticity in the well-characterized and behaviorally important giant interneuron pathway in insects.

Pheromone-evoked potentials and oscillations in the antennal lobes of the sphinx moth Manduca sexta.

Using intra- and extracellular recording methods, we studied the activity of pheromone-responsive projection neurons in the antennal lobe of the moth Manduca sexta. Intracellularly recorded responses of neurons to antennal stimulation with the pheromone blend characteristically included both inhibitory and excitatory stages of various strengths. To observe the activity of larger groups of neurons, we recorded responses extracellularly in the macroglomerular complex of the antennal lobe. The macroglomerular complex is part of a specialized olfactory subsystem and the site of first-order central processing of sex-pheromonal information. Odors such as the pheromone blend and host-plant (tobacco) volatiles gave rise to evoked potentials that were reproducible upon repeated antennal stimulation. Evoked potentials showed overriding high-frequency oscillations when the antenna was stimulated with the pheromone blend or with either one of the two key pheromone components. The frequency of the oscillations was in the range of 30-50 Hz. Amplitude and frequency of the oscillations varied during the response to pheromonal stimulation. Recording intracellular and extracellular activity simultaneously revealed phase-locking of action potentials to potential oscillations. The results suggest that the activity of neurons of the macroglomerular complex was temporally synchronized, potentially to strengthen the pheromone signal and to improve olfactory perception.

Distributed effects of dopamine modulation in the crustacean pyloric network.

It is now clear that neuromodulators can reconfigure a single motor network to allow the generation of a family of related movements. Using dopamine modulation of the 14-neuron pyloric network from the crustacean stomatogastric ganglion as an example, we describe two major mechanisms by which network output is modulated. First, the baseline electrophysiological properties of the network neurons can be altered. Dopamine can affect the activity of each neuron independently. For example, DA modulates IA in nearly every neuron in the pyloric network, but in opposite directions in different cells. Furthermore, DA usually modulates combinations of ionic currents. In some cases, currents with opposing actions on cell excitability are simultaneously affected, and the net response reflects the sum of these opposing effects. Second, neuromodulators can alter the strength of synaptic interactions within the network, quantitatively "rewiring" the network. Every synapse in the network is affected by DA, with some increased and others decreased in strength. DA acts both pre- and postsynaptically to affect transmission: these actions are frequently opposing in sign, and the net response arises as the sum of these opposing actions. Finally, spike-evoked and graded transmission at the same synapse can be oppositely affected by DA. These results emphasize the distributed nature of modulation in motor networks.

Organization of the antennal motor system in the sphinx moth Manduca sexta.

The antennae of the sphinx moth Manduca sexta are multimodal sense organs, each comprising three segments: scape, pedicel, and flagellum. Each antenna is moved by two systems of muscles, one controlling the movement of the scape and consisting of five muscles situated in the head capsule (extrinsic muscles), and the other system located within the scape (intrinsic muscles) and consisting of four muscles that move the pedicel. At least seven motoneurons innervate the extrinsic muscles, and at least five motoneurons innervate the intrinsic muscles. The dendritic fields of the antennal motoneurons overlap one another extensively and are located in the neuropil of the antennal mechanosensory and motor center. The density of motoneuronal arborizations is greatest in the lateral part of this neuropil region and decreases more medially. None of the motoneurons exhibits a contralateral projection. The cell bodies of motoneurons innervating the extrinsic muscles are distributed throughout an arching band of neuronal somata dorsal and dorsolateral to the neuropil of the antennal mechanosensory and motor center, whereas the cell bodies of motoneurons innervating the intrinsic muscles reside mainly among the neuronal somata situated dorsolateral to that neuropil.

Serotonin-induced changes in the excitability of cultured antennal-lobe neurons of the sphinx moth Manduca sexta.

The modulatory actions of 5-hydroxy-tryptamine (5HT or serotonin) on a morphologically identifiable class of neurons dissociated from antennal lobes of Manduca sexta at stages 9-15 of the 18 stages of metamorphic adult development were examined in vitro with whole-cell patch-clamp recording techniques. Action potentials could be elicited from approximately 20% of the cells. These cells were used to examine effects of 5HT (5 x 10(-6) to 5 x 10(-4) M) on cell excitability and action-potential waveform. 5HT increased the number of spikes elicited by a constant depolarizing current pulse and reduced the latency of responses. 5HT also led to broadening of action potentials in these neurons and increased cell input resistance. Modulation of potassium channels by 5HT is likely to contribute to these responses. 5HT causes reversible reduction of at least 3 distinct potassium currents, one of which is described for the first time in this study. Because effects of 5HT on antennal-lobe neurons in culture mimic those observed in situ in the brain of the adult moth, in vitro analysis should contribute to elucidation of the cellular mechanisms that underlie the modulatory effects of 5HT on central olfactory neurons in the moth.

Anatomy of the antennal motoneurons in the brain of the honeybee (Apis mellifera).

This paper describes the morphology and location of the cerebral motoneurons that control the movement of the antennae in the honeybee. The position of each antenna is controlled by two muscle systems; the basal segment (scape) is moved by four muscles within the head capsule, and two muscles within the scape control the distal segments (flagellum) of the antenna. The motor system of the scape is controlled by nine motoneurons, and that of the flagellum by six motoneurons. All of these motoneurons share the dorsal lobe as a common projection area where their dendritic fields overlap extensively. These motoneurons do not have contralateral projections. The cell bodies of the antennal motoneurons are located in the soma layer lateral to the dorsal lobe. The somata for each muscle system are arranged in three clusters; two clusters are located in a region of the cortex dorsal to the dorsal lobe and one cluster is located in the cortex ventral to the dorsal lobe. In the cortex dorsal to the dorsal lobe, one cluster of each muscle system shares the same region. Altogether five groups of cell bodies can be distinguished. Double labeling of the motoneurons and presumptive mechanosensory primary antennal afferents with fluorescent dyes has shown that there is an extensive overlap of axonal projections of antennal mechanosensory afferents with dendritic fields of antennal motoneurons.

A role for calcineurin (protein phosphatase-2B) in the regulation of glutamate release.

Previous studies have shown that 4-aminopyridine (4AP) induced Ca-influx effects the release of glutamate from nerve terminals (synaptosomes) isolated from rat cerebral cortex. We now show that the Ca-dependent component of this release is potentiated by preincubation of the synaptosomes with the immunosuppressant, FK506, an inhibitor of protein phosphatase-2B (calcineurin). FK506 did not inhibit the Ca-independent release of glutamate from a cytosolic pool. Examination of the effect of FK506 on the influx of Ca elicited by 4AP indicated that inhibition of calcineurin activity resulted in an increase of voltage-dependent Ca-influx. Based on these results, we suggest that protein dephosphorylation effected by calcineurin may suppress voltage-dependent Ca-channel activity and in so doing inhibits evoked glutamate release. Activation of calcineurin produced by initial Ca-entry may represent a negative feedback to limit the activity of Ca-channels coupled to the release of glutamate.

Neuromodulation by 5-hydroxytryptamine in the antennal lobe of the sphinx moth Manduca sexta.

Using intracellular recording techniques, we have begun to examine the effects of 5-hydroxytryptamine (5-HT) on antennal-lobe (AL) neurones in the brain of the adult moth Manduca sexta. 5-HT modulated the responses of local interneurones and projection neurones, which were recognized on the basis of well-established electrophysiological criteria, to primary synaptic input elicited by electrical stimulation of the ipsilateral antennal nerve. 5-HT applied at low concentration (10(-8) mol l-1) reduced the excitatory responses evoked by electrical stimulation of the antennal nerve, whereas at high concentration (10(-4) mol l-1), 5-HT enhanced the responses. At 10(-4) mol l1, 5-HT increased cell input resistance, led to broadening of action potentials and caused increased cell excitability in many AL neurones.

Characterization of toxicosis in sheep dosed with blossoms of sacahuiste (Nolina microcarpa).

To characterize more fully sacahuiste (Nolina microcarpa Watson) toxicosis in sheep and to evaluate benefits of supplemental Zn, sheep were dosed intraruminally with sacahuiste blossoms. In Trial 1, eight fine-wool sheep (47 +/- 2 kg BW) were fed alfalfa hay at 1% of BW daily and dosed intraruminally with inflorescences amounting to 1% of BW daily, in three portions per day, for 10 d. Four sheep were dosed intraruminally with aqueous ZnSO4 (30 mg of Zn/kg BW) daily for 3 d before initial sacahuiste dosing and on alternate days thereafter, and four sheep were untreated with Zn. Toxicosis was evident within 24 h after initial sacahuiste dosage, involving inappetence, depression, hypokalemia, hypophosphatemia, hyperbilirubinemia, and elevated serum enzymes (alkaline phosphatase, creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and gamma-glutamyl transpeptidase). One sheep (untreated with Zn) died on d 3. Aqueous ZnSO4 alleviated inappetence and suppressed elevation of serum urea N and creatinine but did not suppress other changes in serum clinical profiles. In Trial 2, sacahuiste inflorescences were ruminally dosed into 12 fine-wool wethers (29 +/- 2 kg BW) in amounts equalling 0, .25, .50, .75% of BW per day, and chopped alfalfa hay was provided at 1.75% of BW per day for 14 d. Sacahuiste inflorescenses dosed at .75% of BW elicited severe toxicosis within 24 h, and dosage at .50 or .25% of BW per day increased (P = .12) serum bilirubin. Ruminal fluid pH, mean particle retention time, and particulate passage rate were not affected (P > .10) by sacahuiste, but ruminal fluid passage rate increased 1.6-fold (P < .10) and ruminal fluid volume decreased by 60% (P < .10) in sheep given inflorescenses amounting to .50% of BW daily. Sacahuiste inflorescenses dosed intraruminally at .75% of BW per day elicited ruminal impaction with severe hepatotoxicosis, and dosages amounting to .50% or .25% of BW per day caused similar trends.

[The systolic time intervals in functional disorders of the thyroid: a simple and fast screening test]. / Die systolischen Zeitintervalle bei Schilddrüsenfunktionsstörungen: ein einfacher und schneller Screening-Test

The systolic time intervals (LVET, PEP, and ratio LVET/PEP) were determined in 53 patients presenting with signs or symptoms of thyroid dysfunction. Patients with clinical evidence of congestive heart failure, with arterial hypertension or old myocardial infarction, and patients receiving cardioactive drugs, were excluded from the study. Thyroid function was evaluated by means of T3-RIA, serum thyroxin and TRH stimulation test.