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M L Lucchi

Publications and source records attributed to M L Lucchi.

At least 19 recordsLinked to original sources
PubMed2006

Central distribution of nociceptive intradental afferent nerve fibers in the rat.

The central distribution of intradental afferent nerve fibers was investigated by combining electron microscopic observations with a selective method for inducing degeneration of the A delta- and C-type afferent fibers. Degenerating terminals were found on the proprioceptive mesencephalic trigeminal neurons and on dendrites in the neuropil of the trigeminal motor nucleus after application of capsaicin to the rat's lower incisor tooth pulp. The results give anatomical evidence of new sites of central projection of intradental A delta- and C-type fibers whereby the nociceptive information from the tooth pulp can affect jaw muscle activity.

Animals↗
PubMed2006

Immunohistochemical localization of alpha(1a)-adrenoreceptors in muscle spindles of rabbit masseter muscle.

The expression of alpha(1a)-adrenoreceptors (alpha(1a)-ARs) within the muscle spindles of rabbit masseter muscle was investigated. The alpha(1a)-ARs were detected by immunohistochemical fluorescent method and examined along the entire length of 109 cross serially sectioned spindles. The sympathetic fibers were visualized by the immunofluorescent labeling of the noradrenaline synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). In order to recognize the intrafusal muscle fiber types, antibodies for different myosin heavy chain isoforms (MyHCI) were used. TH and DBH immunolabeled nerve fibers have been observed within the capsule lamellar layers, in the periaxial fluid space and close to intrafusal muscle fibers. The alpha(1a)-ARs were detected on the smooth muscle cells of the blood vessels coursing in the muscle and in the capsule lamellar layers or within the periaxial fluid space of the spindles. Moreover, at the polar regions of a high percentage (88.1%) of muscle spindles a strong alpha(1a)-ARs immunoreactivity was present on the intrafusal muscle fibers. In double immunostained sections for alpha(1a)-ARs and MyHCI it was evidenced that both bag, and nuclear chain fibers express alpha(1a)-ARs. The receptors that we have detected by immunofluorescence may support a direct control by adrenergic fibers on muscle spindle.

Animals↗
PubMed2000

Density of perfused brain capillaries in the aged rat during the wake-sleep cycle.

Structural and functional age-related changes in brain vasculature might affect the cerebral microcirculation. The present study evaluated the density of perfused brain capillaries and the perfusion fraction (perfused/existing capillaries) in aged rats (24 months) during the states of the wake-sleep cycle (quiet wakefulness, quiet sleep, active sleep) characterized by different levels of brain activation. The number of perfused capillaries was determined by intravascular injection of the fluorescent marker Evans Blue; histochemical staining of the capillary endothelium identified the alkaline-phosphatase (AP) reactive quota of the anatomical population. No sleep-related changes in perfused capillary density were found, and the perfusion fraction in the AP-stained sub-population was high and stable (95%) across the sleep-wake cycle: changing levels of brain activation during sleep do not affect functional capillary density in aged rats.

Aging↗
PubMed1999

Cerebellar afferents from neurons in the extraocular motor nuclei: a fluorescent retrograde double-labeling study in the sheep.

The fluorescent retrograde double labeling technique has been used to identify within the extraocular motor nuclei of the sheep the neurons projecting to the cerebellum and to provide evidence whether they are motor neurons sending collaterals to the cerebellum or a separate population of neurons. The study was performed on eight sheep. The fluorescent tracers used were Fast Blue and the diamidino yellow dihydrochloride. In one and the same animal a fluorescent tracer was injected into the extraocular muscles (EOMs) and the other into bilateral points of the vermal folia II-V and paramedian lobule, or into the vermal folia VI, VIIA and VIIB, or into the underlying fastigial nuclei. Within the oculomotor, trochlear, and abducens nuclei, almost all of the motor neurons were labeled by the tracer injected into the EOMs and only a few cells were fluorescent for the tracer infiltrated into the cerebellum. These latter labelings were present bilaterally, and their number and distribution did not show apparent differences after injecting the paramedian lobule and the vermal folia or the fastigial nucleus. Along the rostrocaudal extent of the oculomotor and trochlear nuclei, the neurons projecting to the cerebellum were intermingled with the motor neurons located in the nuclear area facing the medial longitudinal fasciculus. In the abducens nucleus they were restricted to the caudal pole of the nucleus, which is located ventrolaterally to the genu of the facial nerve. Double-labeled neurons were never found. The absence of double-labeled cells, in spite of the efficiency of the tracer infiltration into the EOMs and into the cerebellum, demonstrates that the cerebellar projections from the extraocular motor nuclei are not collaterals of the motor neurons, but axons of a separate population of neurons.

Afferent Pathways↗
PubMed1998

Collaterals of recurrent laryngeal nerve fibres innervate the thymus: a fluorescent tracer and HRP investigation of efferent vagal neurons in the rat brainstem.

The origin and course of efferent vagal fibers, which innervate the rat thymus, were investigated by a fluorescent retrograde double labeling method, using Fast blue (FB) and Diamidino yellow dihydrochloride (DY) as tracers. In the same animal, one tracer was injected into the cranial portion of the right lobe of the thymus and the other dye was deposited around the cut end of the right recurrent laryngeal nerve. The neuronal population giving origin to the recurrent nerve was mapped by using retrograde labeling with HRP applied to the central stump of the nerve. The HRP retrograde axonal transport showed that most efferent vagal fibers of the recurrent nerve have their perikarya in the nucleus retroambigualis (NRA), nucleus ambiguus (NA), and to a lesser extent in the nucleus retrofacialis (NRF). In fluorescent retrograde double labeling of thymus and recurrent laryngeal nerve both single and double labeled cells were found. The cells labeled by the injections into the thymus were colocalized with the neurons labeled by the tracer deposited in the recurrent laryngeal nerve to the NRA, NA, and NRF. Moreover along the rostrocaudal extent of the NRF and NA double labeled cells were present, showing that some of the thymic efferents are collaterals of the recurrent nerve fibers. Our experiments shown that some thymic vagal fibres originate from neurons of nucleus dorsalis nervi vagi (NDV) as demonstrated both by HRP and FB injected thymuses. The possible role of these efferents in thymic function is briefly discussed.

Amidines↗
PubMed1998

Cerebellar and spinal projections of the coeruleus complex in the duck: a fluorescent retrograde double-labeling study.

The double fluorescent retrograde tracing technique was used to identify, within the coeruleus complex (Co complex) of the duck, the nerve cells projecting to the cerebellar cortex and to the spinal cord. This technique was also used to investigate the possibility that the cerebellar and spinal projections of the Co complex are collaterals of the same axons. In the same animal, nuclear Diamidino yellow dihydrochloride (DY) fluorescent tracer was placed into the cerebellar cortex of folia V-VII, and cytoplasmic fluorescent Fast blue (FB) dye was injected into C3-C4 spinal cord segments. FB labeled multipolar somata and DY fluorescent nuclei were intermingled within the dorsal caudal region of the locus coeruleus (LCo) and within the dorsal division of the nucleus subcoeruleus (dSCo). Moreover, in the LCo, a low proportion of double-labeled neurons (about 3-4% of labelings) was evidenced among single-labeled neurons. In the ventral division of the nucleus subcoeruleus (vSCo), occasional DY labeled nuclei were found, whereas FB-labeled cells were frequently present. The present findings reveal the location of the coeruleocerebellar and coeruleospinal projecting neurons within the Co complex of the duck. They are intermingled in the caudal portion of the LCo and along the rostrocaudal extent of the subjacent dSco. The LCo and the dSCo are the major source of the projections to the folia V-VII, whereas the vSCo contributes very slightly to the innervation of the cerebellar injected areas. Moreover, the double-labeling study demonstrates that in the duck a low percentage of neurons within the ventrolateral portion of the caudal region of the LCo projects both to the cerebellar cortex of folia V-VII and to C3-C4 spinal cord segments via collaterals. Therefore, these neurons simultaneously influence the cerebellar cortex and spinal cord. The possibility that the projections studied are noradrenergic and that they play a role in feeding is discussed.

Afferent Pathways↗
PubMed1997

Mesencephalic trigeminal nucleus neurons supplying the jaw closing muscles have no spinal projection: a fluorescent double-labeling study in birds and mammals.

BACKGROUND: The present study deals with the possibility that the mesencephalic trigeminal nucleus (MeV) neurons that innervate the muscle spindles of the jaw closing muscles may also have collaterals projecting to the cervical spinal cord. At the same time, we reexamine the morphology of these cells and their location within the MeV. METHODS: The fluorescent retrograde tracers Fast Blue (FB) and Diamidino Yellow dihydrochloride (DY) were injected into the jaw closing muscles and C2-C3 spinal cord segments, respectively, of duck, rat, and rabbit in one series of experiments. In a second series of animals, the targets of the tracers were reversed. RESULTS: Retrogradely double-labeled cells (FB+DY) were not found in the MeV. On the contrary, the tracer injected into the muscles retrogradely labeled only large unipolar MeV cells, whereas the tracer injected into C2-C3 spinal cord segments labeled only small multipolar cells which were intermingled with the MeV somata of muscle spindle afferents. CONCLUSIONS: These findings exclude the possibility of spinal projections via collaterals of MeV cells supplying muscle spindles of jaw closing muscles in duck, rat, and rabbit. Moreover, the retrograde double-labeling technique evidences two cellular populations within the MeV of the duck, rat, and rabbit: large unipolar neurons which are the cell bodies of primary afferents from jaw closing muscles and small multipolar cells projecting to the upper cervical spinal cord.

Anatomy, Comparative↗
PubMed1996

Central projections and entries of capsaicin-sensitive muscle afferents.

The entry pathway and central distribution of A delta and C muscle afferents within the central nervous system (CNS) were investigated by combining electron microscopy and electrophysiological analysis after intramuscular injection of capsaicin. The drug was injected into the rat lateral gastrocnemius (LG) and extraocular (EO) muscles. The compound action potentials of LG nerve and the evoked field potentials recorded in semilunar ganglion showed an immediate and permanent reduction in A delta and C components. The morphological data revealed degenerating unmyelinated axons and terminals in the inner sublamina II and in the border of laminae I-II of the dorsal horn at L4-L5 and C1-C2 (subnucleus caudalis trigemini) spinal cord segments. Most degenerating terminals were the central bouton (C) of type I and II synaptic glomeruli. Furthermore, degenerating peripheral axonal endings (V2) presynaptic to normal C were found. Since V2 were previously found degenerated after cutting the oculomotor nerve (ON) or L4 ventral root, we conclude that some A delta and C afferents from LG and EO muscles entering the CNS by ON or ventral roots make axoaxonic synapses on other primary afferents to promote an afferent control of sensory input.

Animals↗
PubMed1996

Brain capillary perfusion during sleep.

Brain capillary perfusion was evaluated in the different states of the wake-sleep cycle-quiet wakefulness (QW), quiet sleep (QS), and active sleep (AS)-in rats. The extent of the perfused capillary network was determined by intravascular distribution of a fluorescent marker. Evans blue (EB); it remained unchanged across the three behavioral conditions, QW, QS, and AS. The anatomical network was assessed by alkaline phosphatase (AP) endothelial staining, which is known to underestimate the number of existing capillaries. The resulting number of AP profiles were, therefore, significantly lower than the number of EB profiles, but the percentage of AP-stained capillaries that were perfused (96%) was also unchanged across the behavioral conditions. The results indicate that no capillary recruitment accompanies the wake-sleep cycle. Capillary surface area is a relevant factor in determining exchanges across the blood-brain barrier. In the absence of capillary recruitment (relative constancy of the surface area), the CBF changes during sleep should preferentially affect flow-limited with respect to diffusion-limited transport.

Animals↗
PubMed1994

Motoneuron organisation of the muscles of the spinal accessory complex of the sheep investigated with the fluorescent retrograde tracer technique.

Retrograde transport of the fluorescent tracers Diamidino Yellow dihydrochloride and Fast Blue was used to determine the location of the spinal nucleus of the accessory nerve in the sheep. We also considered whether in this species the sternocephalic, brachiocephalic, omotransversarius and trapezius muscles, i.e. the muscles of the spinal accessory complex, are supplied by more than one population of motoneurons. The spinal accessory nucleus extends as a single column of neurons from C1 to C7 spinal cord segments and occupies a lateral position within the ventral horn. The most rostral portion of this column is located dorsolaterally, whereas the remaining portion from C2 to C7 occupies a ventrolateral position. At C1 and C4 levels the nucleus also possesses some cells with a medial location. All the muscles of the spinal accessory complex receive their motor innervation both from the spinal accessory nucleus and from motoneurons forming the cervical spinal nerves. A double motor innervation of these muscles is thus present in the sheep.

Accessory Nerve↗
PubMed1993

Orbital pain and unruptured carotid-posterior communicating artery aneurysms: the role of sensory fibers of the third cranial nerve.

Intact aneurysms of the carotid siphon at the point of take-off of the posterior communicating artery may exhibit orbital pain, whether associated with oculomotor palsy or not as a warning symptom prior to rupture. In order to explain this symptom the hypothesis of a sensory pathway within the third cranial nerve, which is liable to compression by the enlarging aneurysm sac, has been investigated. Data from human autopsy material show evidence of sensory ganglion cells within the rootlets of the oculomotor nerve; furthermore, studies in animals prove that the third nerve contains sensory fibers which run proximally along the nerve bundles, enter the brainstem and reach the spinal trigeminal nucleus. These fibers come from the ophthalmic division of the fifth nerve and join the third nerve at the level of the lateral wall of the cavernous sinus. Although a number of questions remain to be solved, the presence of a sensory pattern within the third nerve could account for fronto-orbital pain from enlarging aneurysms impinging on the third nerve itself.

Animals↗
PubMed1993

Localization of motoneurons innervating the extraocular muscles of the sheep by retrograde fluorescent tracers.

Retrograde transport of the fluorescent tracers Fast blue, Evans blue, Diamidino yellow dihydrochloride, and Propidium iodide was used to determine the location of the motoneurons innervating the extraocular muscles of the sheep. An extensive superposition among the motor pools of the oculomotor nucleus (ON) has been observed. In the rostral third of the ON, a considerable merging occurs between obliquus ventralis and rectus medialis motoneurons and also between rectus ventralis and rectus medialis motoneurons. In the middle third of the ON, rectus dorsalis and levator palpebrae superioris motoneurons are intermingled with each other, and also with obliquus ventralis motoneurons dorsally and with rectus medialis motoneurons ventrally. The rostral portion of the trochlear nucleus overlaps with the caudal pole of the ON. The motoneurons innervating the obliquus dorsalis muscle are mainly contralateral with few ipsilateral exceptions. The retractor bulbi muscle receive the innervation by both the abducens and accessory abducens nuclei.

Abducens Nerve↗
PubMed1991

Peripheral territory and neuropeptides of the trigeminal ganglion neurons centrally projecting through the oculomotor nerve demonstrated by fluorescent retrograde double-labeling combined with immunocytochemistry.

The peripheral territories of sheep trigeminal neurons which send their central process to the brainstem through the oculomotor nerve were investigated by the use of fluorescent tracers in double-labeling experiments. For this purpose Diamidino yellow (DY) injection into the oculomotor nerve was combined with Fast blue (FB) injection either into the extraocular muscles (EOMs), or the cornea, or the superior eyelid. Double-labeled DY + FB cells were found in the ophthalmic region of the trigeminal ganglion in addition to single-labeled DY or FB cells. The DY and DY + FB-labeled trigeminal cells were analysed immunocytochemically for their content of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and cholecystokinin-8 (CCK-8)-like. All single-labeled DY cells showed SP-, CGRP- or CCK-8-like immunoreactivity. Double-labeled DY + FB neurons innervating the EOMs were immunoreactive for each of the three peptides, whereas double-labeled neurons supplying the cornea were only CGRP-like positive. The findings suggest that, in the sheep, trigeminal neurons which send their process centrally through the oculomotor nerve supply the EOMs, the cornea, and the superior eyelid and contain neuropeptides which are usually associated with pain sensation.

Animals↗
PubMed1991

The morphology and location of atrial specific granules and the demonstration of atrial natriuretic factor in porcine, lapine and bovine heart by immunoelectronmicroscopy.

The atrial specific granules (ASGs) were studied in samples collected from the right and left auricles of conventionally slaughtered cows (10), pigs (16) and rabbits (8). In addition, the presence of atrial natriuretic factor (ANF) was detected by immunocytochemistry. Mature ASGs, characterized by the presence of highly osmiophilic and electron-dense material surrounded by a membrane, were present in all atrial myoendocrine cells and their diameters ranged from 100 to 470 nm in pigs, from 100 to 235 nm in cattle, and from 125 to 275 nm in rabbits. Immunoelectronmicroscopical studies revealed the presence of ANF in the ASGs of pigs and cattle, whereas anti-ANF polyclonal serum failed to detect any significative reaction in lapine ASGs. The ultrastructural features of the ASGs of pigs, cattle and rabbits described may be useful in comparing the morphological picture of several cardiac endocrine pathological conditions.

Animals↗
PubMed1990

Analysis of the sternotrachealis muscle fibers in some Anseriformes: histochemistry and sex differences.

Histochemical characteristics and sizes of the fibers of the sternotrachealis (ST) muscle have been investigated in some Anseriformes (mallard, Pekin duck, Muscovy duck, and goose) of both sexes. A sexual dimorphism has been shown in the muscle of the species examined. In the mallard and Pekin duck, the male ST muscle shows type IIIA fibers in addition to the type I, IIA, and IIB fibers observed also in the female. In the Muscovy duck, the male muscle has only type I and IIA fibers, whereas the female muscle presents type I fibers and both types IIA and IIB fibers. Moreover, the mean frequencies for each fiber type were significantly different between males and females. In the goose, both male and female muscles present only type I and IIA fibers. In all the species examined, the mean areas of each fiber type are significantly different between male and female, being always larger in the male muscles. The anatomical sexual dimorphism observed in the ST muscle is discussed in relation to function.

Adenosine Triphosphatases↗
PubMed1990

An immunohistochemical approach to the intrafusal fibers of extraocular muscle spindles in sheep, cow, and pig.

Intrafusal muscle fibers of the extraocular muscles (EOMs) of the sheep, cow, and pig were studied histochemically and immunohistochemically. In sheep and cow spindles, three intrafusal fiber types, namely the bag1, bag2, and chain fibers, were identified by a combination of standard histochemical methods and immunohistochemical staining with antibodies selective for slow-tonic (antitonic ALD) and slow twitch (anti-I BA-D5) myosin. The bag1 and bag2 fibers appeared immunologically different on the basis of their differential reactivity with the two antisera. Anti-tonic ALD preferentially stained the bag1 fibers, whereas anti-I BA-D5 labeled the bag2 fibers. Chain fibers did not react with either antisera. In the pig EOM spindles, in general, one bag and some chain intrafusal fibers were identified. The bag fiber was labeled by anti-tonic ALD, but it did not react with the anti-I BA-D5. These findings point to the existence in pig EOM spindles of only one bag fiber antigenically similar to the bag1 fiber of the other species examined.

Adenosine Triphosphatases↗