Tegmentum

The class II cytokine receptor family includes receptors for interferon a/P (lEN a/P) and y (lENy) and IL-10. lEN-y immunoreactivity has been found in neurons in the hypothalamus, cerebral cortex, mammilary nuclei, and dorsal tegmentum. Astrocytes and microglia in vitro can be stimulated to express class II histocompatibiHty complex (MHC-II) antigens by lEN-y, which may be involved in the presentation of antigen to T-ceUs by astrocytes. Thus lEN-y may be critical in CNS-immune function and dysfunction especially in regard to neuronal and gHal apoptotic processes. 

French ED, Dillon K, Wu X Cannabinoids excite dopamine neurons in the ventral tegmentum and substantia nigra. Neuroreport 8 649—632, 1997 Fujinaga M, Maze M Neurobiology of nitrous oxide-induced antinociceptive effects. Mol Neurobiol 25 167-189, 2002... 

Webster, HH and Jones, BE (1988) Neurotoxic lesions of the dorsalateral pontomesencephalic tegmentum-cholinergic cell area in the rat. II Effects upon sleep-waking states. Brain Res. 458 285-302. 

D2 Mostly in striatum, nucleus accumbens and olfactory tubercle but also on neuron cell bodies in substantia nigra and ventral tegmentum where they are the autoreceptors for locally (dendritic) released DA. The loss of specific D2 antagonist binding in the striatum after lesions of the afferent nigro-striatal tract indicates their presynaptic autoreceptor role on terminals there. Other lesion studies have also established D2 receptors on other inputs such as the cortico striatal tract. 

Fiorino, DF, Coury, A, Fibiger, HC and Phillips, AG (1993) Electrical stimulation of reward sites in the ventral tegmentum area increases dopamine transmission in the nucleus acumbers of the rat. Behav. Brain Res. 55 131-141. 

This peptide itself has no selectivity for the two CCK receptors, CCK-A and B, which have so far been established to stimulate IP3/DAG while, like substance P, can close potassium channels to increase neuronal activity. The CCK-B receptor is thought to predominate in the CNS but species differences may make this interpretation difficult. It has a wide distribution in the CNS but is also found in the gut whereas the CCK-A receptor is more restricted but is found in the hypothalamus, hippocampus and in the brainstem. There are high levels of the natural peptide, CCK-8 in cortex, hippocampus, hypothalamus, ventral tegmentum, substantia nigra, brainstem and spinal cord. CCK is one of the most abundant peptides in the brain and CCK co-exists with dopamine, substance P, 5-HT and vasopressin. Interestingly, in the dopamine areas, CCK co-exists in the mesolimbic pathways but in the nigrostriatal projections, the peptide and... 

There is some loss (40-60%) of DA in the nucleus accumbens of the mesolimbic system in the ventral tegmentum (AlO) and cortex at post-mortem but nowhere is it as marked as in the striatum. Some loss of NA, 5-HT, CCK and the enkephalins and of the markers GAD and ChAT (for GABA and ACh) have been reported in the striatum, SN and other areas but these rarely exceed 50% and could be secondary to DA loss. 

The mesolimbic from the ventral tegmentum (VTA, AlO) to the nucleus accumbens, olfactory tubercule, amygdala and pyriform cortex... 

Hedreen, J.C. A direct projection from tegmentum to cortex and hippocampus demonstrated with the Nauta and Fink-Heimer methods. Anat Rec 175 340, 1973. 

Mesocortical A neural pathway that connects the ventral tegmentum to the cortex, particularly the frontal lobes. It is one of the major dopamine pathways in the brain. 

Garzon, M., De Andres, I. Reinoso-Suarez, F. (1998). Sleep patterns after carbachol delivery in the ventral oral pontine tegmentum of the cat. Neuroscience 83, 1137-44. 

Henley, K. 8r Morrison, A. R. (1974). A re-evaluation of the effects of lesions of the pontine tegmentum and locus coeruleus on phenomena of paradoxical sleep in the cat. Acta Neurobiol. Exp. (Wars). 34, 215-32. 

Pal, D. Mallick, B. N. (2004). GABA in pedunculopontine tegmentum regulates spontaneous rapid eye movement sleep by acting on GABAA receptors in freely moving rats. Neurosci. Lett. 365, 200-4. 

Singh, S. Mallick, B. N. (1996). Mild electrical stimulation of pontine tegmentum around locus coeruleus reduces rapid eye movement sleep in rats. Neurosci. Res. 24, 227-35. 

Crochet, S. Sakai, K. (1999b). Effects of microdialysis application of monoamines on the EEG and behavioural states in the cat mesopontine tegmentum. Eur. J. Neurosci. 11, 3738-52. 

Datta, S. Siwek, D. F. (2002). Single cell activity patterns of pedunculopontine tegmentum neurons across the sleep-wake cycle in the freely moving rats. J. Neurosci. Res. 70, 611-21. 

Datta, S., Spoley, E. E. Patterson, E. H. (2001). Microinjection of glutamate into the pedunculopontine tegmentum induces REM sleep and wakefulness in the rat. Am. J. Physiol Regul. Integr. Comp. Physiol 280, 752-9. 

Maloney, K. J., Mainvilie, L. Jones, B. E. (1999). Differential c-Fos expression in cholinergic, monoaminergic, and GABAergic cell groups of the pontomesencephalic tegmentum after paradoxical sleep deprivation and recovery. J. Neurosci 19, 3057-72. 

Tononi, G., Pompeiano, M. Cirelh, C. (1991). Suppression of desynchronized sleep through microinjection of the alpha 2-adrenergic agonist clonidine in the dorsal pontine tegmentum of the cat. Pflugers Arch. 418, 512-18. 

Baghdoyan, H. A., Rodrigo-Angulo, M. L., McCarley, R. W. Hobson, J. A. (1987). A neuroanatomical gradient in the pontine tegmentum for the cholinoceptive induction of desynchronized sleep signs. Brain Res. 414, 245-61. 

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