Cholinergic projections from the pedunculopontine tegmental nucleus contact excitatory and inhibitory neurons in the inferior colliculus
rat; acetylcholine; auditory; brain-stem; plasticity; cells; modulation; neuromodulation; pathways; midbrain; hearing; arousal; acetylcholine-receptors; auditory input; choline acetyltransferase; gabaergic neurons; viral tracing; volume transmission; viral tracing
The inferior colliculus processes nearly all ascending auditory information. Most collicular cells respond to sound, and for a majority of these cells, the responses can be modulated by acetylcholine (ACh). The cholinergic effects are varied and, for the most part, the underlying mechanisms are unknown. The major source of cholinergic input to the inferior colliculus is the pedunculopontine tegmental nucleus (PPT), part of the pontomesencephalic tegmentum known for projections to the thalamus and roles in arousal and the sleep-wake cycle. Characterization of PPT inputs to the inferior colliculus has been complicated by the mixed neurotransmitter population within the PPT. Using selective viral-tract tracing techniques in a ChAT-Cre Long Evans rat, the present study characterizes the distribution and targets of cholinergic projections from PPT to the inferior colliculus. Following the deposit of viral vector in one PPT, cholinergic axons studded with boutons were present bilaterally in the inferior colliculus, with the greater density of axons and boutons ipsilateral to the injection site. On both sides, cholinergic axons were present throughout the inferior colliculus, distributing boutons to the central nucleus, lateral cortex, and dorsal cortex. In each inferior colliculus (IC) subdivision, the cholinergic PPT axons appear to contact both GABAergic and glutamatergic neurons. These findings suggest cholinergic projections from the PPT have a widespread influence over the IC, likely affecting many aspects of midbrain auditory processing. Moreover, the effects are likely to be mediated by direct cholinergic actions on both excitatory and inhibitory circuits in the inferior colliculus.
Noftz WA; Beebe NL; Mellott JG; Schofield BR
Frontiers in Neural Circuits
2020
2020-07-16
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.3389/fncir.2020.00043" target="_blank" rel="noreferrer noopener">10.3389/fncir.2020.00043</a>
Chronic Exposure To Nicotine And Saquinavir Decreases Endothelial Notch-4 Expression And Disrupts Blood-brain Barrier Integrity
acetylcholine-receptors; Biochemistry & Molecular Biology; choline transporter; cigarette-smoke condensate; electron-spin-resonance; endothelial cell toxicity; gene-expression; in-vitro; inhibitors; Neurosciences & Neurology; nicotine; Notch-4; osmotic pumps; parkinsons-disease; perfusion technique; protease; protease inhibitors; proteins; ritonaivir; ROS; saquinqavir; tight junction
Manda V K; Mittapalli R K; Geldenhuys W J; Lockman P R
Journal of Neurochemistry
2010
2010-10
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1111/j.1471-4159.2010.06948.x" target="_blank" rel="noreferrer noopener">10.1111/j.1471-4159.2010.06948.x</a>
MORPHOMETRIC ANALYSIS OF COATED VESICLES IN DEVELOPING RAT MUSCLE-SPINDLES
acetylcholine-receptors; cells; coated vesicles; development; innervation; intrafusal fibers; membrane; morphometry; motor; muscle spindle; Physiology; rat
The incidence of coated vesicles under sarcolemmal surfaces of equatorial, juxtaequatorial and polar regions in developing and adult spindles of the rat soleus muscle was examined by quantitative morphometry of transverse ultrathin sections. Coated vesicles were more numerous: 1) under primary sensory endings than under other types of neuromuscular contacts; 2) under the appositional sarcolemma between neighbouring intrafusal fibres than under free surfaces of the sarcolemma; and 3) in developing than in mature spindles. Factors such as location and age of the animal often interacted to produce an additive effect on the incidence of coated vesicles. Although there was a high incidence of coated vesicles at the postsynaptic surface under sensory terminals of bag2 fibres in 18 and 19 day gestational embryonic rats, it peaked in 4 day postnatal animals. The high incidence of coated vesicles at sensory endings supports the view that coated vesicles mediate neurotrophic interactions between afferents and intrafusal fibres during the critical late gestation and early postnatal time period, as sensory axons first contact their target fibres and exert a maximal directing influence on the differentiation of intrafusal fibre types. In addition, the preferential localization of coated vesicles under appositional rather than free surfaces of developing intrafusal fibres in 0-4 day rats suggests that they play a role in the transport of active substances among intrafusal fibres exhibiting different stages of maturity.
Stephens H; Walro J M; Kucera J
Physiological Research
1992
1992
Journal Article
n/a