OCTOPAMINERGIC MODULATION OF THE FOREWING STRETCH RECEPTOR IN THE LOCUST LOCUSTA MIGRATORIA

1990 ◽  
Vol 149 (1) ◽  
pp. 255-279 ◽  
Author(s):  
JAN-MARINO RAMIREZ ◽  
IAN ORCHARD
Keyword(s):  
Intact Animal ◽  
Locusta Migratoria ◽  
Beat Frequency ◽  
Motor Pattern ◽  
Stretch Receptor ◽  
Maximal Effect ◽  
Naturally Occurring ◽  
Entire Central Nervous System ◽  
Dorsal Unpaired Median ◽  
Stimulation Of

Modulatory actions of various biogenic amines and peptides on the locust forewing stretch receptor (SR) were examined. The response of the SR to sinusoidal wing movements was unaffected by physiological concentrations (5×10−8moll−1) of the peptides AKHI, AKHII, proctolin and FMRFamide. The biogenic amine octopamine, however, enhanced the SR response in a dosedependent manner when injected into the haemolymph of an almost intact animal or perfused over an isolated thorax preparation in which head, abdomen, gut and the entire central nervous system were removed (threshold at 5×10−8moll−1, maximal effect at 5×10−4moH−1 DL-octopamine). The SR was as sensitive to D-octopamine, the naturally occurring isomer of octopamine, as it was to DLoctopamine. Serotonin was equal to octopamine in effectiveness, followed in order of potency by synephrine, metanephrine and tyramine. Dopamine was ineffective. Phentolamine, but not DL-propranolol, antagonized the action of octopamine. The threshold of the modulatory effect of octopamine on the SR suggests that the increased haemolymph octopamine level which occurs during flight is sufficient to increase the SR activity. Two observations suggest that dorsal unpaired median (DUM) cells are involved in the octopaminergic modulation of the SR during flight: (1) selective stimulation of these cells modulated the SR response and this effect was blocked by phentolamine; and (2) a number of DUM cells were activated during flight. These results suggest that the SR activity is enhanced by octopamine following the onset of flight. Since the SR is involved in the control of wing beat frequency, the modulation of the SR might influence the generation of the motor pattern in flying locusts.

Alteration of bursting properties in interneurons during locust flight

1993 ◽  
Vol 70 (5) ◽  
pp. 2148-2160 ◽  
Author(s):  
J. M. Ramirez ◽  
K. G. Pearson
Keyword(s):  
Locusta Migratoria ◽  
Motor Pattern ◽  
Afferent Input ◽  
Proprioceptive Information ◽  
Current Pulses ◽  
Proprioceptive Input ◽  
And Function ◽  
Flight Motor ◽  
Bursting Activity ◽  
Stimulation Of

1. The contribution of bursting properties to the generation of the flight motor pattern was examined for two identified interneurons (interneurons 566 and 567) in the flight system of the locust Locusta migratoria by means of intracellular recording and stimulation techniques. These interneurons are important elements in transmitting proprioceptive information from the hindwing tegula to wing elevator motoneurons. 2. Offset currents injected into these neurons revealed that bursts are triggered in the intact flying animal by synaptic input from tegula afferents (n = 10). These bursts lead to an amplification of proprioceptive input that is crucial for the generation of the intact flight motor pattern. In the absence of afferent input the activity of these neurons remained subthreshold for triggering a burst. This explains why these neurons exhibit only weak rhythmic oscillations in deafferented animals. 3. The property of interneuron 566 to burst was conditional, always being expressed during flight (n = 14) and occurring only occasionally in the quiescent animal. In the absence of flight, stimulation of tegula afferents never evoked bursts in interneuron 566 (n = 7) and depolarizing current pulses evoked weak bursts in only three of nine preparations. In 2 of 14 animals, bursting property of interneuron 566 was enhanced just after the termination of flight. 4. Variability in the bursting property was also found for interneuron 567. In the quiescent animal, tegula-evoked compound excitatory postsynaptic potentials were not sufficient to trigger bursts (n = 3) but depolarizing current pulses evoked always weak rhythmic bursting activity (n = 4). This bursting property was also variable and in one animal we found long-lasting plateau potentials that could be evoked by current injection after flight was elicited several times. 5. The data presented demonstrate that the capacity to burst is conditional in the interneurons 566 and 567. Bursting properties are always induced during flight and function to amplify proprioceptive pathways that are important for the generation of the intact flight motor pattern.

Fictive swimming elicited by electrical stimulation of the midbrain in goldfish

1993 ◽  
Vol 70 (2) ◽  
pp. 765-780 ◽  
Author(s):  
J. R. Fetcho ◽  
K. R. Svoboda
Keyword(s):  
Brain Stimulation ◽  
Beat Frequency ◽  
Motor Pattern ◽  
The Body ◽  
Motor Output ◽  
Stimulus Strength ◽  
Motor Nerves ◽  
Tail Beat ◽  
The Brain ◽  
Stimulation Of

1. We developed a fictive swimming preparation of goldfish that will allow us to study the cellular basis of interactions between swimming and escape networks in fish. 2. Stimulation of the midbrain in decerebrate goldfish produced rhythmic alternating movements of the body and tail similar to swimming movements. The amplitude and frequency of the movements were dependent on stimulus strength. Larger current strengths or higher frequencies of stimulation produced larger-amplitude and/or higher-frequency movements. Tail-beat frequency increased roughly linearly with current strength over a large range, with plateaus in frequency sometimes evident at the lowest and highest stimulus strengths. 3. Electromyographic (EMG) recordings from axial muscles on opposite sides at the same rostrocaudal position showed that stimulation of the midbrain led to alternating EMG bursts, with bursts first on one side, then the other. These bursts occurred at a frequency equal to the tail-beat frequency and well below the frequency of brain stimulation. EMG bursts recorded from rostral segments preceded those recorded from caudal segments on the same side of the body. The interval between individual spikes within EMG bursts sometimes corresponded to the interval between brain stimuli. Thus, whereas the frequency of tail beats and EMG bursts was always much slower than the frequency of brain stimulation, there was evidence of individual brain stimuli in the pattern of spikes within bursts. 4. After paralyzing fish that produced rhythmic movement on midbrain stimulation, we monitored the motor output during stimulation of the midbrain by using extracellular recordings from spinal motor nerves. We characterized the motor pattern in detail to determine whether it showed the features present in the motor output of swimming fish. The fictive preparations showed all of the major features of the swimming motor pattern recorded in EMGs from freely swimming fish. 5. The motor nerves, like the EMGs produced by stimulating midbrain, showed rhythmic bursting at a much lower frequency than the brain stimulus. Bursts on opposite sides of the body alternated. The frequency of bursting ranged from 1.5 to 13.6 Hz and was dependent on stimulus strength, with higher strengths producing faster bursting. Activity in rostral segments preceded activity in caudal ones on the same side of the body. Some spikes within bursts of activity occurred at the same frequency as the brain stimulus, but individual brain stimuli were not as evident as those seen in some of the EMGs. 6. The duration of bursts of activity in a nerve was positively and linearly correlated with the time between successive bursts (cycle time).(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of Kaurane Diterpene Derivatives on Germination and Growth of Lactuca sativa Seedlings

2005 ◽  
Vol 60 (1-2) ◽  
pp. 72-78 ◽  
Author(s):  
Henriete S. Vieira ◽  
Jacqueline A. Takahashi ◽  
Lúcia P. S. Pimenta ◽  
Maria Amélia D. Boaventura
Keyword(s):  
Gibberellic Acid ◽  
Lactuca Sativa ◽  
Naturally Occurring ◽  
Germination And Growth ◽  
Stimulation Of

Kaurenoic and grandiflorenic acid, isolated from Wedelia paludosa (Asteraceae), some derivatives from these acids (alcohols, esters, amides, lactones, oximes) and other naturally occurring kaurane diterpenes were tested for their action on the growth of radical and shoot of Lactuca sativa. Gibberellic acid, GA3, a commercially available phytohormone, belonging to the same class of diterpenes, was also tested. Some of the tested substances showed a remarkable activity either in the inhibition or in stimulation of L. sativa growth. The activity, in some cases, was even higher than that of GA3.

The Function of a Heteromorph Antennule in a Spiny Lobster, Panulirus Argus

1965 ◽  
Vol 43 (1) ◽  
pp. 55-78
Author(s):  
D. M. MAYNARD ◽  
M. J. COHEN
Keyword(s):  
Motor Neurons ◽  
Spiny Lobster ◽  
Panulirus Argus ◽  
Intracellular Recordings ◽  
Afferent Fibre ◽  
The Third ◽  
Naturally Occurring ◽  
Withdrawal Response ◽  
Basic Similarity ◽  
Stimulation Of

1. The effects of electrical and mechanical stimulation upon a ‘naturally occurring’ heteromorph appendage growing in place of one eyestalk in Panulirus argus were examined. The heteromorph resembled the outer flagellum of the antennule in form. 2. Heteromorph stimulation elicited both a generalized withdrawal response, and a specific depression of the third segment and flagellum of the ipsilateral antennule. Such a depression response was also elicited upon stimulation of the ipsilateral outer flagellum of the normal antennule and by no other input investigated. 3. The basic similarity of the two responses was confirmed by electromyography and by intracellular recordings from motor neurons and interneurons within the lobster brain. 4. It was concluded that at least one afferent fibre component from the heteromorph and normal flagellum terminated upon the same interneuron pools, while avoiding others, and that consequently these observations provide evidence for the formation of functional inter-neuronal connexions according to type specificity.

The Control of Changes in Peripheral Sensilla Associated with Feeding in Locusta Migratoria (L.)

1972 ◽  
Vol 57 (3) ◽  
pp. 755-763
Author(s):  
E. A. BERNAYS ◽  
R. F. CHAPMAN
Keyword(s):  
Normal Level ◽  
Electrical Resistance ◽  
Locusta Migratoria ◽  
Corpus Cardiacum ◽  
Corpora Cardiaca ◽  
Diuretic Hormone ◽  
Stretch Receptors ◽  
The Brain ◽  
Maxillary Palps ◽  
Stimulation Of

1. The electrical resistance across the tips of the maxillary palps is not affected by stimulation of the palps, but increases to the normal level found after feeding as a result of distension of the foregut with agar or injection of corpus cardiacum homogenates into the haemolymph. 2. No increase in resistance occurs if the posterior pharyngeal nerves or the frontal connectives are cut. 3. It is inferred that distension of the foregut stimulates stretch receptors which, acting via the posterior pharyngeal nerves, the frontal connectives and the brain, cause the release of hormone from the storage lobes of the corpora cardiaca. This hormone acts on the terminal sensilla of the palps, causing them to close and so increasing the resistance across the palps. 4. Release of the diuretic hormone is controlled via the same pathway.

Stimulation of steroidogenesis in cultured rat adrenocortical cells by unsaturated fatty acids

1995 ◽  
Vol 268 (6) ◽  
pp. R1484-R1490 ◽  
Author(s):  
I. Sarel ◽  
E. P. Widmaier
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Lipid Homeostasis ◽  
Control Mechanisms ◽  
Adrenocortical Cells ◽  
Stimulatory Action ◽  
Apparent Lack ◽  
Naturally Occurring ◽  
Oleic And Linoleic Acids ◽  
Stimulation Of

The hypothesis that the stimulatory action of free fatty acids (FFA) in the hypothalamic-pituitary-adrenocortical (HPA) axis occurs in part at the adrenal cortex was evaluated. Pathophysiological concentrations of oleic and linoleic acids, but not stearic or caprylic acid, stimulated steroidogenesis from cultured rat adrenocortical cells (concentrations eliciting 50% of maximal responses, approximately 60 and 120 microM, respectively), with a latency of 90 min. Maximal stimulation of steroidogenesis by both acids was < 50% of that produced by adrenocorticotropic hormone (ACTH) and was blocked by cycloheximide. The maximal steroidogenic response to ACTH was inhibited approximately 50% by oleic acid. The actions of oleic and linoleic acids were not associated with an increase in adenosine 3',5'-cyclic monophosphate (cAMP) secretion but appeared to require intracellular oxidation. None of the lipids influenced cell viability or corticosterone radioimmunoassay. The latency of the steroidogenic response, the putative requirement for intracellular oxidation, and the apparent lack of involvement of cAMP suggest a mechanism of action of FFA distinct from that of ACTH, yet still requiring protein synthesis. It is concluded that the modulation of steroidogenesis by these abundant naturally occurring lipids may be an important component of the control mechanisms within the HPA pathway in disorders of lipid homeostasis (e.g., obesity, starvation, or diabetes).

scholarly journals Multimodal Medullary Neurons and Correlational Linkages of the Respiratory Network

1999 ◽  
Vol 82 (1) ◽  
pp. 188-201 ◽  
Author(s):  
Zhongzeng Li ◽  
Kendall F. Morris ◽  
David M. Baekey ◽  
Roger Shannon ◽  
Bruce G. Lindsey
Keyword(s):  
Firing Rate ◽  
Nucleus Tractus Solitarius ◽  
Motor Pattern ◽  
Sensory Modality ◽  
Spike Trains ◽  
Negative Feedback Regulation ◽  
Firing Rates ◽  
Respiratory Network ◽  
Cross Correlation Analysis ◽  
Stimulation Of

This study addresses the hypothesis that multiple sensory systems, each capable of reflexly altering breathing, jointly influence neurons of the brain stem respiratory network. Carotid chemoreceptors, baroreceptors, and foot pad nociceptors were stimulated sequentially in 33 Dial-urethan–anesthetized or decerebrate vagotomized adult cats. Neuronal impulses were monitored with microelectrode arrays in the rostral and caudal ventral respiratory group (VRG), nucleus tractus solitarius (NTS), and n. raphe obscurus. Efferent phrenic nerve activity was recorded. Spike trains of 889 neurons were analyzed with cycle-triggered histograms and tested for respiratory-modulated firing rates. Responses to stimulus protocols were assessed with peristimulus time and cumulative sum histograms. Cross-correlation analysis was used to test for nonrandom temporal relationships between spike trains. Spike-triggered averages of efferent phrenic activity and antidromic stimulation methods provided evidence for functional associations of bulbar neurons with phrenic motoneurons. Spike train cross-correlograms were calculated for 6,471 pairs of neurons. Significant correlogram features were detected for 425 pairs, including 189 primary central peaks or troughs, 156 offset peaks or troughs, and 80 pairs with multiple peaks and troughs. The results provide evidence that correlational medullary assemblies include neurons with overlapping memberships in groups responsive to different sets of sensory modalities. The data suggest and support several hypotheses concerning cooperative relationships that modulate the respiratory motor pattern. 1) Neurons responsive to a single tested modality promote or limit changes in firing rate of multimodal target neurons. 2) Multimodal neurons contribute to changes in firing rate of neurons responsive to a single tested modality. 3) Multimodal neurons may promote responses during stimulation of one modality and “limit” changes in firing rates during stimulation of another sensory modality. 4) Caudal VRG inspiratory neurons have inhibitory connections that provide negative feedback regulation of inspiratory drive and phase duration.

Capsaicin-activated bronchial- and alveolar-initiated pathways regulating tracheal ciliary beat frequency

1994 ◽  
Vol 77 (3) ◽  
pp. 1239-1245 ◽  
Author(s):  
M. Eljamal ◽  
L. B. Wong ◽  
D. B. Yeates
Keyword(s):  
Low Dose ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Neural Stimulation ◽  
Short Exposure ◽  
Tracheal Lumen ◽  
Prolonged Stimulation ◽  
Prior Administration ◽  
Stimulation Of ◽  
Ciliary Beat

We questioned whether the prolonged stimulation of ciliary beat frequency (CBF) to a short exposure of low-dose capsaicin (Wong et al. J. Appl. Physiol. 68: 257–2580, 1990) could be due to the activation of indirect pathways involving neural reflexes initiated independently in the bronchi and alveoli. Tracheal CBF (CBFtr) was measured temporally in anesthetized groups of 10 dogs by means of heterodyne-mode correlation analysis laser light scattering. To elucidate the site of the afferent neural stimulation and the efferent mediators affecting the ciliated epithelium, capsaicin (3 nM) aerosol was delivered for 4 min, either predominantly to the bronchi or to the alveolar regions, with use of pulsed aerosol techniques. This resulted in 13 pg of bronchial (85%) and 10 pg of alveolar (96%) capsaicin deposited, which caused marked stimulation of CBFtr with maxima at 7 and 35 min, respectively. Prior administration of aerosolized indomethacin to the bronchi or aerosolized cromolyn to the alveoli inhibited the bronchial and alveolar responses, respectively. Prior administration of aerosolized hexamethonium to the tracheal lumen blocked the stimulatory CBFtr responses from both capsaicin challenges. Ipratropium or propranolol aerosols delivered to the tracheal lumen also inhibited these responses. It is proposed that these pathways comprise one set of sensitive mechanisms to ensure a prolonged stimulation of CBF to effect the removal of secretions and the irritant from the lungs.

Differential effects of UTP, ATP, and adenosine on ciliary activity of human nasal epithelial cells

2001 ◽  
Vol 280 (6) ◽  
pp. C1485-C1497 ◽  
Author(s):  
Diane M. Morse ◽  
Jennifer L. Smullen ◽  
C. William Davis
Keyword(s):  
Epithelial Cells ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Ciliary Activity ◽  
Maximal Effect ◽  
Ciliary Beating ◽  
Mediated Effects ◽  
Human Nasal Epithelium ◽  
Human Nasal Epithelial Cells ◽  
Sustained Responses

The purinergic regulation of ciliary activity was studied using small, continuously superfused explants of human nasal epithelium. The P2Y2 purinoceptor (P2Y2-R) was identified as the major purinoceptor regulating ciliary beat frequency (CBF); UTP (EC50 = 4.7 μM), ATP, and adenosine-5′- O-(3-thiotriphosphate) elicited similar maximal responses, approximately twofold over baseline. ATP, however, elicited a post-peak sustained plateau in CBF (1.83 ± 0.1-fold), whereas the post-peak CBF response to UTP declined over 15 min to a low-level plateau (1.36 ± 0.16-fold). UDP also stimulated ciliary beating, probably via P2Y6-R, with a maximal effect approximately one-half that elicited by P2Y2-R stimulation. Not indicated were P2Y1-R-, P2Y4-R-, or P2Y11-R-mediated effects. A2B-receptor agonists elicited sustained responses in CBF approximately equal to those from UTP/ATP [5′-( N-ethylcarboxamido)adenosine, EC50 = 0.09 μM; adenosine, EC50 = 0.7 μM]. Surprisingly, ADP elicited a sustained stimulation in CBF. The ADP effect and the post-peak sustained portion of the ATP response in CBF were inhibited by the A2-R antagonist 8-( p-sulfophenyl)theophylline. Hence, ATP affects ciliary activity through P2Y2-R and, after an apparent ectohydrolysis to adenosine, through A2BAR.

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