Origin and course of an afferent component of the facial nerve within the central nervous system

Summary The mesencephalic nucleus of trigeminal gives rise to an afferent component of the facial nerve. This nucleus contains large unipolar afferent cell bodies which give rise to an axon which courses caudally through the brainstem and exits via the facial nerve to terminate distal to the stylomastoid foramen.This work was supported by National Aeronautics and Space Administration Grant No. NAS 9-15213.     

Destruction of afferent nerve terminals in the inner ear of frog by aminooxyacetic acid

Summary The drug aminooxyacetic acid, which inhibits GABA-transaminase, destroys the afferent nerve endings in the inner ear of the frog. The efferent nerve endings and the sensory cells are not affected.     

17β-estradiol in vitro affects Na-dependent and depolarization-induced Ca2+ transport in rat brain synaptosomes

Effects of 17-estradiol (E₂) in vitro on Na-dependent Ca²⁺ efflux from, and depolarization-induced Ca²⁺ uptake into, the nerve cell were studied with the use of synaptosomes isolated from the brain stem, mesencephalic reticular formation (MRF), caudate nucleus and the hippocampus of long-term ovariectomized adult female rats. It was found that E₂ (1) at a concentration of 10 nM or lower, stimulates Na-dependent Ca²⁺ efflux in the caudate nucleus and hippocampus, and does not affect the efflux in MRF and brain stem; (2) at concentrations above 10 nM has no effect on the Ca²⁺ efflux in any of the four structures investigated; and (3) produces a biphasic effect on the depolarization-induced Ca²⁺ uptake, increasing it in all structures except MRF at 10 nM concentration, and decreasing it at concentrations higher than 10 nM, irrespective of the structure investigated. These results suggest that E₂, acting at extranuclear sites, modulates synaptic transmission via alterations of Ca²⁺ transport mechanisms in nerve endings.     

Histofluorescence of catecholamines and visualization of retrograde transported peroxidase in the same tissue section and in the same neuron]

The demonstration of fluorescent catecholamines and horseradish peroxidase (HRP) in the same neuron has been achieved in the Rat in two ways: by submitting vibratome sections to a modified glyoxylic acid fluorescence method followed by the usual procedure to reveal HRP; or by combining the last procedure with the cryostat technique of Chiba et coll. After HRP injection into the striatum or the nucleus accumbens of the Rat, non-fluorescent HRP labelled neurons were observed in the substantia nigra and the ventral tegmental area respectively, in addition to the HRP labelled fluorescent dopaminergic neurons.     

Concerning the ionic basis of presynaptic inhibition.

The superfused rat cuneate nucleus has been used to investigate the sensitivity of primary afferent terminals and of evoked primary afferent depolarization (PAD) to alterations in extracellular K+ and Cl- ions levels. Results indicate that PAD is caused by an efflux of Cl- from primary afferent terminals rather than by an increase in extracellular K+.     

Uptake and transport of exogenous peroxidase in the masticatory muscles of the cat. Localization of motor neurons]

In the present work, a topographical localization of masticatory muscle motoneurons was undertaken. Horseradish peroxydase injected in each muscle can be transported in the retrograde direction to the corresponding motoneurons cell bodies. Jaw-closing muscle motoneurons were identified in the dorsal part of the motor trigeminal nucleus whereas jaw-opening muscle motoneurons were observed in the ventro-medial region.     

Destruction of afferent nerve terminals in the inner ear of frog by aminooxyactic acid.

The drug aminooxyacetic acid, which inhibits GABA-transaminase, destroys the afferent nerve ending in the inner ear of the frog. The efferent nerve endings and the sensory cells are not affected.     

Myosin isoenzymes during in vivo and in vitro differentiation of chick muscles

Muscle fibers differentiated, in vitro, from myoblasts of embryonic Pectoralis (presumptive fast) and embryonic Adductor magnus (presumptive slow) muscles synthesise the same type of myosin, which is identical to the type synthesised in day 10 embryonic muscles. This type of myosin comigrates with the third isozyme of the adult fast-twitch muscle. There is no change in the kind of myosin in cultures aged from 2 to 7 weeks, whereas during the in vivo differentiation of the same muscles, new isozymes appear which are different in the two muscles. With regard to myosin, the muscle fibers differentiated, in vitro, from myoblasts of fast or slow muscles expressed the same phenotype.     

Monoamine oxidase inhibition by d-amphetamine in ganglia and nerve endings

Summary The inhibition of monoamine oxidase (MAO) activity by d-amphetamine was measured in homogenates of cat superior cervical ganglion and nictitating membrane, using tyramine (TM) and noradrenaline (NA) as substrates. In both tissues, d-amphetamine was shown to be a competitive inhibitor of the oxidation of TM. The Ki for d-amphetamine, as a MAO inhibitor, was lower in the ganglia than in the peripheral nerve endings.Supported by a Contract from the National Research Council of Argentina (CONICET) (Res. 67/79).     

Concerning the ionic basis of presynaptic inhibition

Summary The superfused rat cuneate nucleus has been used to investigate the sensitivity of primary afferent terminals and of evoked primary afferent depolarization (PAD) to alterations in extracellular K⁺ and Cl^– ion levels. Results indicate that PAD is caused by an efflux of Cl^– from primary afferent terminals rather than by an increase in extracellular K⁺.     

Nerves and muscles regulating feather follicle movements in the chicken

Summary It was found that most feather follicles possess more than a single muscle system but only single nerve endings were observed in a feather follicle. It seems that muscles exist which antagonize each other. Anastomoses of nerves orginating from different sources and flowing of mixed nerves into the feather follicle could explain the antagonistic action of the muscles on the feather follicle.Partially supported by a grant from the Israel Egg and Poultry Board.     

Suboesophageal DUM neurones are part of the antennal motor system of locusts and crickets

Summary The muscles which move the antennae of locusts and crickets are innervated by motoneurones of the deutocerebral part of the brain. In addition, these muscles receive axon collaterals of two dorsal, unpaired, median (DUM) neurones which are located in the suboesophageal ganglion. These DUM neurones also send axons towards the retrocerebral glandular complex.     

New data on the precise location of the lacrimo-muconasal nucleus of the rat

Summary Three methods (axonal degeneration, retrograde labelling with HRP and Golgi's silver impregnation) were used in the identification of a group of cells located in the ventrolateral part of the reticular formation of the pons, which are postulated to form the lacrimo-muconasal nucleus of the rat.     

Peptidergic innervation of the temporomandibular disk in the rat

Summary The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.     

Peptidergic innervation of the temporomandibular disk in the rat

The peptidergic innervation of the temporomandibular disk was investigated in the postnatal young rat by using an indirect immunofluorescence method. Calcitonin gene-related peptide-containing nerve fibers were located around the blood vessels and terminated as free nerve endings in the disk. These nerve fibers may be of a sensory nature.     

Electroacupuncture: Effects on digastric muscle activities in the rat jaw-opening reflex

Summary Electroacupuncture suppressed the late component of the digastric muscle activity in the rat jaw-opening reflex evoked by buccal skin stimulation, while it scarcely affected the early component. When the jaw-opening reflex was elicited by tooth pulp stimulation, the activity of the digastricus was well suppressed in its whole phase.Acknowledgment. The authors wish to express thanks to Prof. M. Ichioka for his interest in this work and to Miss M. Oguro for her technical assistance. This work was supported by grants (No. 56770852 and No. 56480301 1981) from the Ministry of Education, Science and Culture of Japan.     

Neuropeptides in pelvic afferent pathways

Summary Neurochemical and pharmacological experiments have raised the possibility that several neuropeptides including, vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), substance P, calcitonin gene-related peptide (CGRP), neurokinin A, cholecystokinin (CCK) and opioid peptides may be transmitters in afferent pathways to the pelvic viscera. These substances are widely distributed in: 1) nerve fibers in the pelvic organs, 2) visceral afferent neurons in the lumbosacral dorsal root ganglia and 3) at sites of afferent termination in the spinal cord. Double, staining immunocytochemical techniques have shown that more than one peptide can be localized in individual visceral afferent neurons and that neuronal excitatory (VIP, substance P, CCK) and inhibitory peptides (leucine enkephalin) can coexist in the same afferent cell. Studies with the neurotoxin, capsaicin, indicate that peptidergic afferent pathways are, involved in the initiation of central autonomic reflexes as well as peripheral axon reflexes which modulate smooth muscle activity, facilitate transmission in automatic ganglia and trigger local inflammatory responses.     

Neuropeptides in pelvic afferent pathways

Neurochemical and pharmacological experiments have raised the possibility that several neuropeptides including, vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine amide (PHI), substance P, calcitonin gene-related peptide (CGRP), neurokinin A, cholecystokinin (CCK) and opioid peptides may be transmitters in afferent pathways to the pelvic viscera. These substances are widely distributed in: 1) nerve fibers in the pelvic organs, 2) visceral afferent neurons in the lumbosacral dorsal root ganglia and 3) at sites of afferent termination in the spinal cord. Double staining immunocytochemical techniques have shown that more than one peptide can be localized in individual visceral afferent neurons and that neuronal excitatory (VIP, substance P, CCK) and inhibitory peptides (leucine enkephalin) can coexist in the same afferent cell. Studies with the neurotoxin, capsaicin, indicate that peptidergic afferent pathways are involved in the initiation of central autonomic reflexes as well as peripheral axon reflexes which modulate smooth muscle activity, facilitate transmission in automatic ganglia and trigger local inflammatory responses.     

Selectivity of alterations in skeletal fibers in chronic Chagas' disease of the mouse

In mice chronically infected with Trypanosoma cruzi, the masseter muscle (rich in type II fibers) was devoid of inflammatory infiltrates and parasites. In contrast, other muscles, composed of type I and II fibers, showed a decrease of type I fibers, parasites and lesions, suggesting that in T. cruzi infection type I muscle fibers are selectively damaged.     

Vagal afferent innervation of the pylorus and the upper small intestine studied in the rat with the horseradish peroxidase technique

The neuronal tracer horseradish peroxidase was injected into different segments of the gastrointestinal in the rat, in order to study the vagal afferent innervation. In the nodose ganglia the extent of labeling was greater in the experiments on the gastric antrum and pylorus than in the experiments on the first part of the small intestine. Vagal afferents are scarce in the upper duodenum and originate mainly from the left nodose ganglion.