Dorsal root recording relevant for mating reflexes in female rats: Identification of receptive fields and effects of peripheral denervation

1975 ◽  
Vol 6 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Lee-Ming Kow ◽  
Donald W. Pfaff
Keyword(s):  
Dorsal Root ◽  
Receptive Fields ◽  
Female Rats

Mechanical sensitivity of group III and IV afferents from posterior articular nerve in normal and inflamed cat knee

1986 ◽  
Vol 55 (4) ◽  
pp. 635-643 ◽  
Author(s):  
P. Grigg ◽  
H. G. Schaible ◽  
R. F. Schmidt
Keyword(s):  
Sciatic Nerve ◽  
Knee Joint ◽  
Conduction Velocity ◽  
Mechanical Stimulation ◽  
Dorsal Root ◽  
Receptive Fields ◽  
Group Iv ◽  
Mechanical Sensitivity ◽  
Group Iii ◽  
Stimulation Of

Recordings were performed from sciatic nerve or dorsal root filaments in 28 cats to study single group III (conduction velocity 2.5-20 m/s) and group IV (conduction velocity less than 2.5 m/s) units supplying the knee joint via the posterior articular nerve (PAN). In seven of these cats the knee joint had been inflamed artificially. Recordings from sciatic nerve filaments revealed responses to local mechanical stimulation of the joint in only 3 of 41 group IV units and in 12 of 18 group III units from the normal joint. In the inflamed joint 14 of 36 group IV units and 24 of 36 group III units were excited with local mechanical stimulation. In recordings from dorsal root filaments (normal joint) 4 of 11 group IV units and 7 of 13 group III units were activated by stimulating the joint locally. In the normal joint four group IV units (recorded from dorsal root filaments) responded only to rotations against the resistance of the tissue, whereas the majority of the fibers did not respond even to forceful movements. Group III units with local mechanosensitivity in the normal joint reacted strongly or weakly to movements in the working range of the joint or only to movements against resistance of the tissue. In the inflamed joint, group IV fibers (recorded in sciatic nerve filaments) with detectable receptive fields responded strongly to gentle movements or only to movements against resistance of tissue. Some did not react to movements. Group III units reacted strongly or weakly to gentle movements or only to movements against resistance of the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Responses of neurons in and near the thalamic ventrobasal complex of the rat to stimulation of uterus, cervix, vagina, colon, and skin

1993 ◽  
Vol 69 (2) ◽  
pp. 557-568 ◽  
Author(s):  
K. J. Berkley ◽  
G. Guilbaud ◽  
J. M. Benoist ◽  
M. Gautron
Keyword(s):  
Receptive Fields ◽  
The Body ◽  
Female Rats ◽  
Caudal Part ◽  
Response Characteristics ◽  
The Core ◽  
Ventrobasal Complex ◽  
Gentle Pressure ◽  
Somatic Receptive Fields ◽  
Stimulation Of

1. Previous studies in the rat and other species have shown that neurons in and near the ventrobasal complex (VB) can be activated by various visceral as well as somatic stimuli. 2. This study examined the responses of 84 single neurons in and near the rostral 2/3 of VB in 19 adult female rats in estrus to mechanical stimulation of the skin (brush, pressure, noxious pinch) and 4 different visceral stimuli, as follows: distension of both uterine horns, mechanical probing of the vagina, gentle pressure against the cervix, and distension of the colon. The rats were studied while under moderate gaseous anesthesia (33% O2-67% N2O + 0.5% halothane) and paralyzed (pancuronium bromide). 3. Of 77 neurons tested with both somatic and visceral stimuli, 70 were responsive to one type and/or the other. Responses to somatic stimuli were immediate with brief afterdischarges to the pinch stimuli. In contrast, responses to visceral stimuli were delayed an average of 9 s with long afterdischarges averaging 2 min. Most viscerally responsive neurons (74%) had somatic receptive fields, often (44%) to noxious pinch. 4. Of the 70 responsive neurons, 43 (61%) responded to 1 or more of the 4 visceral stimuli, primarily with excitation. Most of these 43 neurons (71%) were responsive to uterine distension, whereas fewer responded to stimulation of the cervix (45%), vagina (29%), or colon (34%). 5. Viscerally responsive neurons were preferentially located in regions bordering or near VB. Only 6 of 22 neurons within the core of VB (27%) responded to visceral stimuli, in contrast with 37 of 48 neurons bordering or near VB (77%). 6. The six viscerally responsive neurons within VB all had somatic receptive fields located primarily on the caudal part of the body and were responsive to only one or two of the four visceral stimuli, usually the uterus. The 37 viscerally responsive neurons bordering or near VB were of 3 types. Neurons of the first type (n = 15) were scattered throughout the areas bordering VB and responded to both somatic and visceral stimuli much like VB neurons, except that they showed more visceral convergence. Neurons of the second type (n = 11) were concentrated at the rostral and dorsal borders of VB and responded only to visceral stimuli, mainly the uterus. Neurons of the third type (n = 11) were concentrated ventrally and had very complex, long-lasting and history-dependent response characteristics to both visceral and somatic stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Impact of Dorsal Root Ganglia Cryoextract on Histological Steatures in Dices and Contractility of Uterus in Differently Aged Rats

2021 ◽  
Vol 31 (3) ◽  
pp. 258-267
Author(s):  
Hanna Nesteruk ◽  
◽  
Viktoriya Ustichenko ◽  
Nataliya Alabedalkarim ◽  
Volodymyr Padalko ◽  
...  
Keyword(s):  
Dorsal Root Ganglia ◽  
Isometric Contraction ◽  
Dorsal Root ◽  
Contractile Activity ◽  
Reproductive Age ◽  
Female Rats ◽  
Saline Control ◽  
Histological Structure ◽  
Aged Rats ◽  
Uterine Contractile

To date, the number of women giving birth to their first child in late reproductive age is increasing around the world. This stipulates a need in designing the new approaches to restore the uterine contractile activity. In this paper, the histological features of uterus and its contractile activity have been experimentally studied in differently aged rats after the dorsal root ganglia cryoextract (DRGCE) administration. The cryoextract was derived from dorsal root ganglia of neonatal piglets by three-fold freezing down to –196°C in saline, followed by thawing at room temperature, homogenization and centrifugation. Here, we used the female rats of reproductive age (RA, 6-month-old) and those of late reproductive age (LRA, 14-month-old). Animals of both age groups received intraperitoneally either DRGCE (experimental groups) or saline (control groups) for 9 days by 0.2 ml. To days 28–29 after administration beginning the animals were sacrificed and the uterine fragments were taken for histological examination and study of oxytocin (OT)-induced uterine contractile activity (UCA). The strength of OT-induced uterine isometric contraction was found to decrease by 28.6% in LRA rats vs. the RA ones. The DRGCE administration to LRA rats increased the UCA indices, namely the contractile frequency, contractile amplitude and strength of isometric contraction augmented by 25, 9.8 and 30% respectively, as compared with the group of the same age without DRGCE introduction. This effect was observed on the background normal uterine histological structure and unchanged myometrial thickness.

Responses of lumbosacral spinal units to mechanical stimuli related to analysis of lordosis reflex in female rats

1980 ◽  
Vol 43 (1) ◽  
pp. 27-45 ◽  
Author(s):  
L. M. Kow ◽  
F. P. Zemlan ◽  
D. W. Pfaff
Keyword(s):  
Sensory Neurons ◽  
Single Unit ◽  
Receptive Fields ◽  
Female Rats ◽  
Mechanical Stimuli ◽  
Firing Rates ◽  
Mixed Response ◽  
Spinal Segments ◽  
Necessary And Sufficient ◽  
Gray Units

1. To analyze further the sensory mechanisms for triggering the lordosis reflex, single-unit (n = 345) activity was recorded extracellularly from spinal segments L5-S1 of urethan-anesthetized female rats. Unit responses to pressure on the skin (necessary and sufficient for evoking lordosis) and other mechanical stimuli were studied. 2. Units were classified according to their responses to the battery of mechanical stimuli: 16% of the units responded only to pressure. The majority of these pressure-responsive units were excited, while a few were inhibited or responded differently, depending on the site stimulated; 52% did not respond to pressure, but responded to brushing, muscle-joint, and/or visceral stimulation, or did not respond at all. The remaining 32% responded to pressure plus other forms of stimulation. 3. Units responding only to the movement of individual types of hair tended to be located in the dorsal horn, more dorsal than units responding only to pressure (found primarily in the intermediate gray). Units responding to subdermal stimulation were usually found at greater depths. Segmental and somatotopic distributions of spinal units observed were very similar to those reported for cat (3) and monkey (5). 4. Compared to primary sensory units (28), spinal units had higher resting firing rates, more complicated responses to a given stimulus, a wider variety of unit types, and much larger receptive fields. These comparisons tend to indicate convergence of primary sensory neurons onto individual spinal units. 5. The range of pressure thresholds of pressure-responsive units is comparable to the range effective for triggering lordosis. We postulate that excitation of units responding only to pressure is centrally involved in triggering the lordosis reflex. Those units not responding to pressure are probably irrelevant for this behavior. Presently undetermined are the roles of units with complex or mixed-response types.

Colonic irritation in the rat sensitizes urinary bladder afferents to mechanical and chemical stimuli: an afferent origin of pelvic organ cross-sensitization

2006 ◽  
Vol 290 (6) ◽  
pp. F1478-F1487 ◽  
Author(s):  
Elena E. Ustinova ◽  
Matthew O. Fraser ◽  
Michael A. Pezzone
Keyword(s):  
Substance P ◽  
Urinary Bladder ◽  
Receptive Fields ◽  
Pelvic Organ ◽  
Female Rats ◽  
Sprague Dawley ◽  
Trinitrobenzenesulfonic Acid ◽  
C Fibers ◽  
Bladder Afferents ◽  
Chemical Stimuli

Chronic pelvic pain (CPP) disorders frequently overlap. We have demonstrated that acute and chronic colonic irritation can lead to neurogenic cystitis. We hypothesize that acute colonic irritation can sensitize urinary bladder afferents to mechanical and chemical stimuli. Single-unit afferent activity was recorded from fine filaments of the pelvic nerve in urethane-anesthetized Sprague-Dawley female rats before and 1 h after intracolonic administration of trinitrobenzenesulfonic acid (TNBS). Only spontaneously active afferents with receptive fields in the bladder and conduction velocities <2.5 m/s (unmyelinated C-fibers) were studied. Mechanical sensitivity was tested by bladder distension (BD) during saline infusion, whereas chemical sensitivity was tested with intravesical capsaicin, bradykinin, or substance P. Colonic irritation increased the resting firing rate of bladder afferents twofold (1.0 ± 0.2 vs. 0.49 ± 0.2 impulses/s, P < 0.05). Moreover, at low-pressure BDs (10–20 mmHg), a greater percentage of afferents exhibited increased activity following TNBS (73 vs. 27%, P < 0.05). Although the magnitude of the afferent response to BD was unchanged at low pressures, the response was greatly enhanced at pressures 30 mmHg and above (2.36 ± 0.56 vs. 8.55 ± 0.73 impulses/s, P < 0.05). Responses to capsaicin, bradykinin, and substance P were also significantly enhanced following TNBS, and all responses were blocked by bladder denervation. In rats, colonic irritation sensitizes urinary bladder afferents to noxious mechanical and chemical stimuli. Interruption of the neural input to the bladder minimized this effect, suggesting a local afferent pathway from the colon. Thus, the overlap of CPP disorders may be a consequence of pelvic afferent cross-sensitization.

GABAA and 5-HT3 Receptors Are Involved in Dorsal Root Reflexes: Possible Role in Periaqueductal Gray Descending Inhibition

2001 ◽  
Vol 86 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Yuan Bo Peng ◽  
Jing Wu ◽  
William D. Willis ◽  
Daniel R. Kenshalo
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Receptive Fields ◽  
Periaqueductal Gray ◽  
Sprague Dawley ◽  
Descending Inhibition ◽  
Pharmacological Agents ◽  
Nociceptive Transmission ◽  
Inhibitory Circuits ◽  
Central Excitability

The dorsal root reflex (DRR) is a measure of the central excitability of presynaptic inhibitory circuits in the spinal cord. Activation of the periaqueductal gray (PAG), a center for descending inhibition of spinal cord nociceptive transmission, induces release of variety of neurotransmitters in the spinal cord, including GABA and serotonin (5-HT). GABA has been shown to be involved in generation of DRRs. In this study, pharmacological agents that influence DRRs and their possible mechanisms were investigated. DRRs were recorded in anesthetized rats from filaments teased from the cut central stump of the left L4or L5 dorsal root, using a monopolar recording electrode. Stimulating electrodes were placed either on the left sciatic nerve or transcutaneously in the left foot. Animals were paralyzed and maintained by artificial ventilation. Drugs were applied topically to the spinal cord. A total of 64 units were recorded in 34 Sprague-Dawley rats. Peripheral receptive fields were found for nine of these units. In these units, DRRs were evoked by brush, pressure, and pinch stimuli. Nine units were tested for an effect of electrical stimulation in the periaqueductal gray on the DRRs. In eight cases, DRR responses were enhanced following PAG stimulation. The background activity was 4.2 ± 1.9 spikes/s (mean ± SE; range: 0–97.7; n = 57). The responses to agents applied to the spinal cord were (in spikes/s): artificial cerebrospinal fluid, 7.1 ± 3.6 (range: 0–86.9; n = 25); 0.1 mM GABA, 16.8 ± 8.7 (range: 0–191.0; n = 22); 1.0 mM GABA, 116.0 ± 26.5 (range: 0.05–1001.2; n = 50); and 1.0 mM phenylbiguanide (PBG), 68.1 ± 25.3 (range: 0–1,073.0; n = 49). Bicuculline (0.5 mM, n = 27) and ondansetron (1.0 mM, n = 10) blocked the GABA and PBG effects, respectively ( P < 0.05). Significant cross blockade was also observed. It is concluded that GABAA receptors are likely to play a key role in the generation of DRRs, but that 5-HT3 receptors may also contribute. DRRs can be modulated by supraspinal mechanisms through descending systems.

Similar Electrophysiological Changes in Axotomized and Neighboring Intact Dorsal Root Ganglion Neurons

2003 ◽  
Vol 89 (3) ◽  
pp. 1588-1602 ◽  
Author(s):  
Chao Ma ◽  
Yousheng Shu ◽  
Zheng Zheng ◽  
Yong Chen ◽  
Hang Yao ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Receptive Fields ◽  
Input Resistance ◽  
Spinal Nerve ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
Ganglion Neurons

We investigated electrophysiological changes in chronically axotomized and neighboring intact dorsal root ganglion (DRG) neurons in rats after either a peripheral axotomy consisting of an L5 spinal nerve ligation (SNL) or a central axotomy produced by an L5 partial rhizotomy (PR). SNL produced lasting hyperalgesia to punctate indentation and tactile allodynia to innocuous stroking of the foot ipsilateral to the injury. PR produced ipsilateral hyperalgesia without allodynia with recovery by day 10. Intracellular recordings were obtained in vivo from the cell bodies (somata) of axotomized and intact DRG neurons, some with functionally identified peripheral receptive fields. PR produced only minor electrophysiological changes in both axotomized and intact somata in L5 DRG. In contrast, extensive changes were observed after SNL in large- and medium-sized, but not small-sized, somata of intact (L4) as well as axotomized (L5) DRG neurons. These changes included (in relation to sham values) higher input resistance, lower current and voltage thresholds, and action potentials with longer durations and slower rising and falling rates. The incidence of spontaneous activity, recorded extracellularly from dorsal root fibers in vitro, was significantly higher (in relation to sham) after SNL but not after PR, and occurred in myelinated but not unmyelinated fibers from both L4 (9.1%) and L5 (16.7%) DRGs. We hypothesize that the changes in the electrophysiological properties of axotomized and intact DRG neurons after SNL are produced by a mechanism associated with Wallerian degeneration and that the hyperexcitability of intact neurons may contribute to SNL-induced hyperalgesia and allodynia.

Spinal estrogen attenuates the exercise pressor reflex but has little effect on the expression of genes regulating neurotransmitters in the dorsal root ganglia

2006 ◽  
Vol 100 (3) ◽  
pp. 958-964 ◽  
Author(s):  
Petra M. Schmitt ◽  
Kishorchandra Gohil ◽  
Marc P. Kaufman
Keyword(s):  
Spinal Cord ◽  
Mrna Expression ◽  
Dorsal Root ◽  
Pressor Response ◽  
Muscle Afferents ◽  
Female Rats ◽  
Opioid Antagonist ◽  
Exercise Pressor Reflex ◽  
Static Contraction ◽  
Pressor Reflex

Previously, our laboratory showed that estrogen, topically applied to the spinal cord, attenuated the exercise pressor reflex in female cats (Schmitt PM and Kaufman MP. J Appl Physiol 95: 1418–1424, 2003; 98: 633–639, 2005). The attenuation was gender specific and was in part opioid dependent. Our finding that the μ- and δ-opioid antagonist naloxone was only able to partially restore estrogen’s attenuating effect on the pressor response to static contraction suggested that estrogen affected an additional pathway, involving the dorsal root ganglion (DRG). Estrogen has been described to stimulate transcription within 10 min of its application to the DRG, raising the possibility that rapid genomic effects on neurotransmitter production may have contributed to estrogen’s effect on the exercise pressor reflex. This prompted us to test the hypothesis that estrogen modulated the pressor response to static contraction by influencing gene expression of the neurotransmitters released by the thin-fiber muscle afferents that evoke the exercise pressor reflex. We confirmed in decerebrated female rats that topical application of estrogen (0.01 μg/ml) to the lumbosacral spinal cord attenuated the pressor response to static muscle contraction (from 10 ± 3 to 1 ± 1 mmHg; P < 0.05). DRG were then harvested postmortem, and changes in mRNA expression were analyzed. GeneChip analysis revealed that neither estrogen nor contraction alone changed the mRNA expression of substance P, the neurokinin-1 receptor, CGRP, NGF, the P2X3 receptor, GABAA and GABAB, the 5-HT3A and 5-HT3B receptor, N-methyl-d-aspartate and non- N-methyl-d-aspartate receptors, opioid receptors, and opioid-like receptor. Surprisingly, however, contraction stimulated the expression of neuropeptide Y in the DRG in the presence and absence of estrogen. We conclude that estrogen does not attenuate the exercise pressor reflex through a genomic effect in the DRG.

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