Colliculi

Localization CNS Hippocampus (CA1, CA3, DG), septum, amygdala, raphe nuclei CNS Striatum, hippocampus (CA1), substantia nigra, globus pallidus, superior colliculi, spinal cord, raphe nuclei CNS like 5-HT1B but at lower densities. CNS Caudate putamen, parietal cortex, fronto-parietal motor cortex, olfactory tubercle, amygdala CNS Cortex, Thalamus, olfactory bulb (rat), claustrum (g-pig), hippocampus (CA3), spinal cord. 

In this cell, the tonic firing of the neuron during this behavior is increased by amphetamine. This result is consistent with our finding that neostriatal units projecting to the pars reticulata are inhibited by amphetamine. The resulting disinhibition of these nigral units may, in turn, increase their tonic inhibitory control over their target stmetures, such as the deep layers of the superior colliculis (Chevalier et al. 1985). the thalamus (Deniau and Chevalier 1985) and the PPN. These output stmetures are known to affect the motor behaviors that amphetamine influences (Di Chiara et al. 1979). 

The 5-HT4 receptor is a member of the seven transmembrane-spanning G protein-coupled family of receptors (GPCR) and constitutes an important subtype of the class of serotonin (5-HT) receptors. Initially, the 5-HT4 receptor was characterized in the neuronal cell culture [3] of mouse colliculi and was shown to be positively coupled to adenylyl cyclase. The effect of serotonin was mimicked by the 5-HT4 receptor agonists, BIMU 1 and BIMU 8, and was blocked by the 5-HT4... 

Location Area postrema Cortex (low density) vagal efferents Superior colliculi Hippocampus Cortex, Hippocampus Olfactory bulb Cerebellum Habenula Hippocampus Striatum Amygdala Cortex Hypothalamus Hippocampus Cortex Olfactory bulb... 

Substantia nigra, globus pallidus, dorsal subiculum, superior colliculi Non-selective pinodol, propanolol selective partial agonists CP-93, 129 Possible clinical use of antagonists antidepressants 5-HTj25 receptors... 

PAM crosses the blood-brain barrier with difficulty. 2-PAM in rat brain, 10 min after injection, is only about 5-12% of that in plasma higher percentages are in the more heavily vascularized areas, such as cerebral and cerebellar cortex and inferior colliculi.34 This low brain-to-blood ratio persists, but over the next 6 h the brain and blood come closer to equilibrium as the blood... 

The 5-HT4 receptors modulate the activities of channels and transporters by increasing cAMP levels. These include activation of L-type Ca2+ channels (326), chloride currents in human jejunal mucosa and rat distal colon (330,331), and the If pacemaker current in atrial myocytes (332) and stimulation of aldosterone release from the adrenal glands (333,334), striatal dopamine release (324), hippocampal and frontal cortex acetylcholine release (335,336), and hippocampal 5-HT release (337). 5-HT4 receptors also inhibit various channels, including a KV3.2-like delayed rectifier K+ channel (303), a voltage-activated K+ channel in colliculi neurons (320,338), a Ca2+-activated, afterhyperpolariz-ing, and K+ current in hippocampus (325). 

Fagni L, Dumuis A, Sebben M, Bockaert J. The 5-HT4 receptor subtype inhibits K+ current in colliculi neurones via activation of a cyclic AMP-dependent protein kinase. Br J Pharmacol 1992 105 973-939. 

Medium-high density of D2 receptors was found in the islands of Calleja, ventral pallidum, zona incerta, GP, central amygdala, in some cells of the anterior lobe of the pituitary, and at several sites in the forebrain the laterodorsal septal area, hippocampus, subiculum, lateral habenula, STh, lateral mammillary bodies. D2 receptors were also found with a medium-high density in various cortical fields prefrontal, anterior cingulate, entorhinal and perirhinal cortices. In the brain stem, medium-high density of D2 receptors was found in the VTA, SNc, ventral SNr, parabrachial nucleus, superior and inferior colliculi, dorsal raphe nucleus and locus coeruleus. 

The areas of the brain that retained the greatest concentrations of the label after intravenous Injection of [ H]BZ Into cats (16) were motor cortex, sensory cortex, caudate nucleus, lateral geniculate, and medial geniculate Smaller concentrations were retained In thalamus, hippocampus, hypothalamus, medulla oblongata, colliculi, cerebellar cortex, the pyramids of the medulla, cerebral white matter, and cerebellar white matter ... 

Part of the brain that includes the inferior and superior colliculi and the substantia nigra. 

The midbrain consists of a number of structures, including the inferior colliculi, the superior colliculi, and tlic substantia nigra. The inferior colliculi form part of the auditory system. The superior colliculi function in localization of visual stimuli. These structures are specifically involved with localization of stimuli and mediation of reflexes. The actual recognition and interpretation of visual and auditory stimuli take place elsewhere in the brain (sec the section on the cerebral cortex). 

Inferior colliculi (ko- lik-yu-lT) Midbrain structures that control sound localization (Chapter 3). 

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