scholarly journals Optogenetic activation of mechanically insensitive afferents in mouse colorectum reveals chemosensitivity

2016 ◽  
Vol 310 (10) ◽  
pp. G790-G798 ◽  
Author(s):  
Bin Feng ◽  
Sonali C. Joyce ◽  
G. F. Gebhart
Keyword(s):  
De Novo ◽  
Visceral Pain ◽  
Ex Vivo ◽  
Significant Proportion ◽  
Receptive Fields ◽  
Critical Factor ◽  
Sensory Innervation ◽  
Hypertonic Solution ◽  
Mechanical Stimuli ◽  
Generator Potential

The sensory innervation of the distal colorectum includes mechanically insensitive afferents (MIAs; ∼25%), which acquire mechanosensitivity in persistent visceral hypersensitivity and thus generate de novo input to the central nervous system. We utilized an optogenetic approach to bypass the process of transduction (generator potential) and focus on transformation (spike initiation) at colorectal MIA sensory terminals, which is otherwise not possible in typical functional studies. From channelrhodopsin2-expressing mice (driven by Advillin-Cre), the distal colorectum with attached pelvic nerve was harvested for ex vivo single-fiber recordings. Afferent receptive fields (RFs) were identified by electrical stimulation and tested for response to mechanical stimuli (probing, stroking, and stretch), and afferents were classified as either MIAs or mechanosensitive afferents (MSAs). All MIA and MSA RFs were subsequently stimulated optically and MIAs were also tested for activation/sensitization with inflammatory soup (IS), acidic hypertonic solution (AHS), and/or bile salts (BS). Responses to pulsed optical stimuli (1–10 Hz) were comparable between MSAs and MIAs whereas 43% of MIAs compared with 86% of MSAs responded tonically to stepped optical stimuli. Tonic-spiking MIAs responded preferentially to AHS (an osmotic stimulus) whereas non-tonic-spiking MIAs responded to IS (an inflammatory stimulus). A significant proportion of MIAs were also sensitized by BS. These results reveal transformation as a critical factor underlying the differences between MIAs (osmosensors vs. inflammatory sensors), revealing a previously unappreciated heterogeneity of MIA endings. The current study draws attention to the sensory encoding of MIA nerve endings that likely contribute to afferent sensitization and thus have important roles in visceral pain.

scholarly journals A130 RETROGRADE TRACING ANALYSIS OF THE SENSORY INNERVATION OF THE MOUSE COLON

2020 ◽  
Vol 3 (Supplement_1) ◽  
pp. 150-151
Author(s):  
S Osman ◽  
A E Lomax
Keyword(s):  
Visceral Pain ◽  
Receptive Fields ◽  
Fluorescence Emission ◽  
Distal Colon ◽  
Proximal Colon ◽  
Sensory Innervation ◽  
Afferent Neurons ◽  
Drg Neurons ◽  
Fluorescence Emission Spectra ◽  
Fast Blue

Abstract Background Visceral pain is a primary symptom of many gastrointestinal diseases. One feature of visceral pain is its vague localization. We hypothesized that overlap in the receptive fields of spinal primary afferent neurons that innervate the gut may contribute to this vague localization. Many studies have confirmed that the proximal and distal colon are mainly innervated by spinal afferent neurons with cell bodies in thoraco-lumbar and lumbo-sacral dorsal root ganglia (DRG), respectively. However, no murine studies have examined whether individual DRG neurons simultaneously innervate both proximal and distal colon. Aims To determine the extent of overlap in receptive fields of colon-projecting DRG neurons. Methods C57BL/6 mice (n=8) were anesthetized, and two retrograde neuronal tracers with distinct fluorescence emission spectra (Fast blue and DiI) were injected separately into the smooth muscle layers of proximal and distal colon. Mice were left for 10–13 days for dye transport, before being euthanized. Thoraco, lumbar and lumbo-sacral DRGs (T8-13, L1-4, L5-S2) were dissected and fixed in 4% paraformaldehyde overnight. 12μm cryostat sections were obtained and analyzed using a fluorescent microscope equipped with filter cubes that detect Fast blue and DiI. Results When DiI was injected into the proximal colon, we observed labelling to be highest in T8-13 DRG with 12.6 +/- 4.5% of cell bodies labelled, followed by L1-4 was (8.2 +/- 1.4%) and in L5-S2 (6.5 +/- 0.8%). DiI injections into the distal colon resulted in labelling of similar numbers of neurons labelled in T8-13 and L1-4 ganglia, whereas half as many neurons were labelled in L5-S2 ganglia. This data shows that the majority of spinal afferent innervation of the colon originates in thoracolumbar DRG. Most importantly, 26.4% and 17.6% of thoracolumbar and lumbo-sacral DRG neurons labelled by Fast blue injection into the proximal colon were also double-labelled by DiI injected into the distal colon. Similarly, 16.6% and 13.8% of neurons in thoracolumbar and lumbosacral DRG labelled by Fast blue injection into the distal colon were double-labelled by DiI injected into the proximal colon. Conclusions These data reveal a surprisingly large number of DRG neurons that innervate the colon have receptive fields that cover both the proximal and distal colon, which may contribute to the poor spatial localization of pain emanating from the colon. Funding Agencies CCC, CIHR

scholarly journals Experimental Setting for Applying Mechanical Stimuli to Study the Endothelial Response of Ex Vivo Vessels under Realistic Pathophysiological Environments

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 671
Author(s):  
Ana Osuna ◽  
Anna Ulldemolins ◽  
Hector Sanz-Fraile ◽  
Jorge Otero ◽  
Núria Farré ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Low Cost ◽  
Technical Information ◽  
Rabbit Aorta ◽  
Pressure Waveform ◽  
Mechanical Stimuli ◽  
Experimental Setting ◽  
Endothelial Response ◽  
Flow Through ◽  
Open Source Hardware

This paper describes the design, construction and testing of an experimental setting, making it possible to study the endothelium under different pathophysiological conditions. This novel experimental approach allows the application of the following stimuli to an ex vivo vessel in a physiological bath: (a) a realistic intravascular pressure waveform defined by the user; (b) shear stress in the endothelial layer since, in addition to the pressure waveform, the flow through the vessel can be independently controlled by the user; (c) conditions of hypo/hyperoxia and hypo/hypercapnia in an intravascular circulating medium. These stimuli can be applied alone or in different combinations to study possible synergistic or antagonistic effects. The setting performance is illustrated by a proof of concept in an ex vivo rabbit aorta. The experimental setting is easy to build by using very low-cost materials widely available. Online Supplement files provide all the technical information (e.g., circuits, codes, 3D printer drivers) following an open-source hardware approach for free replication.

Aging does not alter the mechanosensitivity of the p38, p70S6k, and JNK2 signaling pathways in skeletal muscle

2005 ◽  
Vol 98 (4) ◽  
pp. 1562-1566 ◽  
Author(s):  
Troy A. Hornberger ◽  
R. D. Mateja ◽  
E. R. Chin ◽  
J. L. Andrews ◽  
K. A. Esser
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathways ◽  
Ex Vivo ◽  
Mechanical Stimuli ◽  
S6 Kinase ◽  
Diminished Capacity ◽  
Ribosomal S6 Kinase ◽  
Passive Stretch ◽  
Old Mice ◽  
Dependent Mechanism

The capacity for skeletal muscle to recover its mass following periods of unloading (regrowth) has been reported to decline with age. Although the mechanisms responsible for the impaired regrowth are not known, it has been suggested that aged muscles have a diminished capacity to sense and subsequently respond to a given amount of mechanical stimuli (mechanosensitivity). To test this hypothesis, extensor digitorum longus muscles from young (2–3 mo) and old (26–27 mo) mice were subjected to intermittent 15% passive stretch (ex vivo) as a source of mechanical stimulation and analyzed for alterations in the phosphorylation of stress-activated protein kinase (p38), ribosomal S6 kinase (p70S6k), and the p54 jun N-terminal kinase (JNK2). The results indicated that the average magnitude of specific tension (mechanical stimuli) induced by 15% stretch was similar in muscles from young and old mice. Young and old muscles also revealed similar increases in the magnitude of mechanically induced p38, p70S6k (threonine/serine 421/424 and threonine 389), and JNK2 phosphorylation. In addition, coincubation experiments demonstrated that the release of locally acting growth factors was not sufficient for the induction of JNK2 phosphorylation, suggesting that JNK2 was activated by a mechanical rather than a mechanical/growth factor-dependent mechanism. Taken together, the results of this study demonstrate that aging does not alter the mechanosensitivity of the p38, p70S6k, and JNK2 signaling pathways in skeletal muscle.

scholarly journals The Regularity of Sustained Firing Reveals Two Populations of Slowly Adapting Touch Receptors in Mouse Hairy Skin

2010 ◽  
Vol 103 (6) ◽  
pp. 3378-3388 ◽  
Author(s):  
Scott A. Wellnitz ◽  
Daine R. Lesniak ◽  
Gregory J. Gerling ◽  
Ellen A. Lumpkin
Keyword(s):  
Fluorescent Protein ◽  
Ex Vivo ◽  
Receptive Fields ◽  
Receptor Subtypes ◽  
Type I ◽  
Genetic Dissection ◽  
Merkel Cells ◽  
Simple Method ◽  
Green Fluorescent ◽  
Nerve Recordings

Touch is initiated by diverse somatosensory afferents that innervate the skin. The ability to manipulate and classify receptor subtypes is prerequisite for elucidating sensory mechanisms. Merkel cell–neurite complexes, which distinguish shapes and textures, are experimentally tractable mammalian touch receptors that mediate slowly adapting type I (SAI) responses. The assessment of SAI function in mutant mice has been hindered because previous studies did not distinguish SAI responses from slowly adapting type II (SAII) responses, which are thought to arise from different end organs, such as Ruffini endings. Thus we sought methods to discriminate these afferent types. We developed an epidermis-up ex vivo skin–nerve chamber to record action potentials from afferents while imaging Merkel cells in intact receptive fields. Using model-based cluster analysis, we found that two types of slowly adapting receptors were readily distinguished based on the regularity of touch-evoked firing patterns. We identified these clusters as SAI (coefficient of variation = 0.78 ± 0.09) and SAII responses (0.21 ± 0.09). The identity of SAI afferents was confirmed by recording from transgenic mice with green fluorescent protein–expressing Merkel cells. SAI receptive fields always contained fluorescent Merkel cells ( n = 10), whereas SAII receptive fields lacked these cells ( n = 5). Consistent with reports from other vertebrates, mouse SAI and SAII responses arise from afferents exhibiting similar conduction velocities, receptive field sizes, mechanical thresholds, and firing rates. These results demonstrate that mice, like other vertebrates, have two classes of slowly adapting light-touch receptors, identify a simple method to distinguish these populations, and extend the utility of skin–nerve recordings for genetic dissection of touch receptor mechanisms.

Abstract 290: Haemogenic Endocardium Contribute To Definitive Hematopoiesis During Cardiogenesis

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Haruko Nakano ◽  
Xiaoqian Liu ◽  
Armin Arshi ◽  
Ben van Handel ◽  
Rajkumar Sasidharan ◽  
...  
Keyword(s):  
De Novo ◽  
Ex Vivo ◽  
Embryonic Stem ◽  
Circulatory System ◽  
Lineage Tracing ◽  
Mouse Heart ◽  
Heart Tube ◽  
Cardiac Progenitors ◽  
Definitive Hematopoiesis

The circulatory system is the first functional organ system that develops during mammalian life. Accumulating evidences suggest that cardiac and endocardial cells can arise from a single common progenitor cell during mammalian cardiogenesis. Notably, these early cardiac progenitors express multiple hematopoietic transcription factors, consistent with previous reports. Indeed, a close relationship among cardiac, endocardial and hematopoietic lineages has been suggested in fly, zebrafish, and embryonic stem cell in vitro differentiation models. However, it is unclear when, where and how this hematopoietic gene program is in operation during in vivo mammalian cardiogenesis. Hematopoietic colony assay suggests that mouse heart explants generate myeloids and erythroids in the absence of circulation, suggesting that the heart tube is a de novo site for the definitive hematopoiesis. Lineage tracing revealed that putative cardiac-derived Nkx2-5+/Isl1+ endocardial cells give rise to CD41+ hematopoietic progenitors that contribute to definitive hematopoiesis in vivo and ex vivo during embryogenesis earlier than in the AGM region. Furthermore, Nkx2-5 and Isl1 are both required for the hemogenic activity of the endocardium. Together, identification of Nkx2-5/Isl1-dependent hemogenic endocardial cells (1) adds hematopoietic component in the cardiogenesis lineage tree, (2) changes the long-held dogma that AGM is the only major source of definitive hematopoiesis in the embryo proper, and (3) represents phylogenetically conserved fundamental mechanism of cardio-vasculo-hematopoietic differentiation pathway during the development of circulatory system.

FC 099DECLINING PERITONEAL HOST DEFENCES REVEALED BY EX-VIVO CYTOKINE RELEASE ASSAY OF PERITONEAL DIALYSIS EFFLUENT CELLS

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Rebecca Herzog ◽  
Lisa Daniel-Fischer ◽  
Isabel Sobieszek ◽  
Christoph Aufricht ◽  
Klaus Kratochwill
Keyword(s):  
Ex Vivo ◽  
Significant Proportion ◽  
Host Defence ◽  
Clinical Staging ◽  
Continuous Exposure ◽  
Immune Competence ◽  
Cytokine Release ◽  
Acute Peritonitis ◽  
Tnf Α ◽  
Release Assay

Abstract Background and Aims Infectious complications occur in a significant proportion of PD patients, limiting long-term applicability. Reduced peritoneal immune-competence, caused by the continuous exposure to PD-fluids, has been described as a therapy-related pathomechanisms, prompting the need for a tool to assess the functional peritoneal immune status. We established an ex-vivo stimulation assay to test host defence mechanisms in only 9ml of PD-effluent. The aim of this study was to analyse basal inflammation and immune-competence in the general PD population at routine conditions to evaluate the assay as surrogate parameter of immune competence and linking it to PD vintage and clinical outcome parameters. Method 147 of 284 (51.8%) adult and paediatric PD patients treated between April 2013 and September 2020 at the local Department of Nephrology were included in the analysis. The study was approved by the local ethics committee and was conducted in accordance with the Declaration of Helsinki. Patients were exclusively treated with neutral pH/multi-chamber PD fluids during the glucose dwells. The majority of the 558 included PD-effluent samples were obtained during standard 4-hours peritoneal equilibration tests (PET) with 3.86% glucose containing PDF. Samples from the pre-PET dwell and at PET time points 1-hour and 4-hours were collected and immediately processed. Additional effluent samples were obtained during unscheduled hospitalization and in the event of an acute peritonitis. Effluent samples were collected directly from the drainage bags into standard 9 ml additive-free sample tubes. For ex-vivo stimulation, 100 ng/ml toll-like receptor (TLR) 4 agonist LPS and TLR2 agonist Pam3Cys were added to the effluent in the 9 ml collection tubes in duplicates and incubated at 37°C for 24h. Unstimulated samples kept in parallel were used as controls. IL-6 and TNF-α concentrations were measured with ELISA in the supernatants. Results Ex-vivo stimulation of peritoneal cells significantly increased the IL-6 and TNF-α release compared to unstimulated controls and resulted in a dwell-time dependent increase, with a significant lower cytokine released at the 1h PET time point. To assess local inflammation IL-6 levels of crude effluent were determined. IL-6 concentrations remained stable over time on PD. Interestingly, we were able to show higher IL-6 levels in CAPD patients in comparison to APD. As chronic exposure to PD-fluids has been shown to dampen the peritoneal immune competence, consecutive peritoneal effluent bags, obtained from patients were analysed. In this subcohort of 183 4h-PET effluents we found a decline in cytokine secretion with time on PD (IL-6 r=-0.27, p=0.00015, TNFa r=-0.25, p=0.00071). In a subgroup the ex-vivo cytokine release of effluent samples from patients with an acute peritonitis was assessed. IL-6 levels of acute peritonitis effluent samples did not differ from the stimulated IL-6 levels of effluent samples without acute peritonitis (2.45 pg/mL vs 2.31 pg/mL, p=0.85, t-test) suggesting that the assay seemingly represents the in-vivo host-defence cytokine release accurately. Conclusion The study provides evidence of a correlation of declining local host defence and duration of PD-therapy. It supports the hypothesis of PD duration-dependent progressive impairment of the ability of the peritoneal immune cells to secrete cytokines in response to a pathogenic stimulus and thereby dampening the global peritoneal immuno-competence. This suggests the utility of this clinically feasible ex-vivo induced cytokine-release assay in peritoneal effluent as a surrogate of the functional peritoneal immune competence. Future analyses need to evaluate the assay as a tool to predict common clinical outcomes and define reference values to facilitate stratification of patient populations, clinical staging and to guide novel therapeutic interventions.

Primary Afferent Neurons Innervating Guinea Pig Dura

1997 ◽  
Vol 77 (1) ◽  
pp. 299-308 ◽  
Author(s):  
Geoffrey M. Bove ◽  
Michael A. Moskowitz
Keyword(s):  
Guinea Pig ◽  
Superior Sagittal Sinus ◽  
Receptive Fields ◽  
Mechanical Stimuli ◽  
Afferent Neurons ◽  
Primary Afferent Neurons ◽  
Primary Afferent ◽  
Response Properties ◽  
Thermal Thresholds ◽  
Sagittal Sinus

Bove, Geoffrey M. and Michael A. Moskowitz. Primary Afferent Neurons Innervating Guinea Pig Dura. J. Neurophysiol. 77: 299–308, 1997. We made recordings from filaments of guinea pig nasociliary nerve to study response properties of afferent axons innervating the anterior superior sagittal sinus and surrounding dura mater. We analyzed 38 units in 14 experiments. Units were initially located with the use of mechanical stimuli, and were then characterized by their conduction velocity and sensitivities to mechanical, thermal, and chemical stimuli. Single-unit recordings revealed innervation of dura and superior sagittal sinus by slowly conducting axons, mostly in the unmyelinated range. The receptive fields were 1–30 mm2, and typically had one to three punctate spots of highest sensitivity. All units tested responded to topical application of chemical agents. Ninety-seven percent of units responded to 10−5 M capsaicin, 79% responded to a mixture of inflammatory mediators, and 37% responded to an acidic buffer (pH 5). These data underline the importance of chemical sensitivity in intracranial sensation. Heat and cold stimuli evoked responses in 56 and 41% of units tested, respectively. Although the response patterns during heating were typical of polymodal nociceptors innervating other tissues, the thresholds were lower than for other tissues (32.3–42°C). Cooling led to a phasic discharge, with thresholds between 25 and 32°C. Although units had different combinations of responses to mechanical, chemical, and thermal stimuli, when grouped by their sensitivities the groups did not differ regarding mechanical thresholds or presence of ongoing activity. This suggests that meningeal primary afferents are relatively homogeneous. Sensitivities of these units are in general consistent with nociceptors, although the thermal thresholds differ. These data provide the first detailed report of response properties of intracranial primary afferent units, likely to be involved in transmission of nociception and possibly mediation of intracranial pain.

Changes in the response properties of neurons in the ventroposterior lateral thalamic nucleus of the raccoon after peripheral deafferentation

1996 ◽  
Vol 75 (6) ◽  
pp. 2441-2450 ◽  
Author(s):  
D. D. Rasmusson
Keyword(s):  
Receptive Field ◽  
Thalamic Nucleus ◽  
Receptive Fields ◽  
Field Size ◽  
Mechanical Stimuli ◽  
Sensory Pathways ◽  
Average Latency ◽  
Somatotopic Map ◽  
Almost All ◽  
Stimulation Of

1. Single neurons in the ventroposterior lateral thalamic nucleus were studied in 10 anesthetized raccoons, 4 of which had undergone amputation of the fourth digit 4-5 mo before recording. Neurons with receptive fields on the glabrous skin of a forepaw digit were examined in response to electrical stimulation of the “on-focus” digit that contained the neuron's receptive field and stimulation of an adjacent, “off-focus” digit. 2. In normal raccoons all neurons responded to on-focus stimulation with an excitation at a short latency (mean 13 ms), whereas only 63% of the neurons responded to off-focus digit stimulation. The off-focus responses had a longer latency (mean 27.2 ms) and a higher threshold than the on-focus responses (800 and 452 microA, respectively). Only 3 of 32 neurons tested with off-focus stimulation had both a latency and a threshold within the range of on-focus values. Inhibition following the excitation was seen in the majority of neurons with both types of stimulation. 3. In the raccoons with digit removal, the region of the thalamus that had lost its major peripheral input (the “deafferented” region) was distinguished from the normal third and fifth digit regions on the basis of the sequence of neuronal receptive fields within a penetration and receptive field size as described previously. 4. Almost all of the neurons in the deafferented region (91%) were excited by stimulation of one or both adjacent digits. The average latency for these responses was shorter (15.3 ms) and the threshold was lower than was the case with off-focus stimulation in control animals. These values were not significantly different from the responses to on-focus stimulation in the animals with digit amputation. 5. These results confirm that reorganization of sensory pathways can be observed at the thalamic level. In addition to the changes in the somatotopic map that have been shown previously with the use of mechanical stimuli, the present paper demonstrates an improvement in several quantitative measures of single-unit responses. Many of these changes suggest that this reorganization could be explained by an increased effectiveness of preexisting, weak connections from the off-focus digits; however, the increase in the proportion of neurons responding to stimulation of adjacent digits may indicate that sprouting of new connections also occurs.

scholarly journals Non-synaptic Cell-Autonomous Mechanisms Underlie Neuronal Hyperactivity in a Genetic Model of PIK3CA-Driven Intractable Epilepsy

2021 ◽  
Vol 14 ◽  
Author(s):  
Achira Roy ◽  
Victor Z. Han ◽  
Angela M. Bard ◽  
Devin T. Wehle ◽  
Stephen E. P. Smith ◽  
...  
Keyword(s):  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Genetic Model ◽  
Ex Vivo ◽  
Significant Proportion ◽  
Intractable Epilepsy ◽  
Therapeutic Interventions ◽  
Hippocampal Pyramidal Neurons ◽  
Phosphoinositide 3 Kinase

Patients harboring mutations in the PI3K-AKT-MTOR pathway-encoding genes often develop a spectrum of neurodevelopmental disorders including epilepsy. A significant proportion remains unresponsive to conventional anti-seizure medications. Understanding mutation-specific pathophysiology is thus critical for molecularly targeted therapies. We previously determined that mouse models expressing a patient-related activating mutation in PIK3CA, encoding the p110α catalytic subunit of phosphoinositide-3-kinase (PI3K), are epileptic and acutely treatable by PI3K inhibition, irrespective of dysmorphology. Here we report the physiological mechanisms underlying this dysregulated neuronal excitability. In vivo, we demonstrate epileptiform events in the Pik3ca mutant hippocampus. By ex vivo analyses, we show that Pik3ca-driven hyperactivation of hippocampal pyramidal neurons is mediated by changes in multiple non-synaptic, cell-intrinsic properties. Finally, we report that acute inhibition of PI3K or AKT, but not MTOR activity, suppresses the intrinsic hyperactivity of the mutant neurons. These acute mechanisms are distinct from those causing neuronal hyperactivity in other AKT-MTOR epileptic models and define parameters to facilitate the development of new molecularly rational therapeutic interventions for intractable epilepsy.

Re-innervation of axolotl limbs - II. Sensory nerves

1975 ◽  
Vol 190 (1098) ◽  
pp. 59-75 ◽  
Keyword(s):  
Tactile Stimulation ◽  
Receptive Fields ◽  
Sensory Information ◽  
Extracellular Recording ◽  
Sensory Nerves ◽  
Sensory Innervation ◽  
Contralateral Limb ◽  
Innervation Patterns ◽  
Control Limb ◽  
Left And Right

Segmental sensory receptive fields in axolotl hindlimb skin were mapped during extracellular recording of nerve responses to light tactile stimulation. Normally, cutaneous sensory innervation patterns for a given pair of left and right hindlimbs were similar, but there was variability among animals. Individual cutaneous fibres innervated a solitary receptive field whose borders were sharply defined. When spinal nerves were crushed or cut and allowed to regrow the receptive fields re-established were similar to those on the normal contralateral limb. However, many single cutaneous fibres innervated multiple receptive fields. After cutting and interchanging the two major limb nerve branches, regenerating cutaneous nerves tended to innervate skin toward which they were directed, and receptive fields did not resemble the patterns on the control limb skin. This contrasts with the results following the same operations on the motor innervation where patterns of re-innervation do resemble the control. Regenerating cutaneous fibres apparently cannot relocate their respective original cutaneous addresses, but readily re-innervate foreign skin areas. Nerves regenerating after a crush or cut appear to follow mechanical and/or biochemical orienting clues within the nerve trunks for restoration of typical innervation patterns. It is not known how the axolotl central nervous system copes with cutaneous sensory information from mislocated nerve terminals.

Sign in / Sign up

Export Citation Format

Share Document