Central cerebellum

The distribution of endosulfan and endosulfan sulfate was evaluated in the brains of cats given a single intravenous injection of 3 mg/kg endosulfan (Khanna et al. 1979). Peak concentrations of endosulfan in the brain were found at the earliest time point examined (15 minutes after administration) and then decreased. When tissue levels were expressed per gram of tissue, little differential was observed in distribution among the brain areas studied. However, if endosulfan levels were expressed per gram of tissue lipid, higher initial levels were observed in the cerebral cortex and cerebellum than in the spinal cord and brainstem. Loss of endosulfan was most rapid from those areas low in Upid. Endosulfan sulfate levels peaked in the brain at 1 hour postadministration. In contrast, endosulfan sulfate levels in liver peaked within 15 minutes postadministration. The time course of neurotoxic effects observed in the animals in this study corresponded most closely with endosulfan levels in the central nervous system tissues examined. 

Both nicotinic and muscarinic receptors are widespread in the CNS. Muscarinic receptors with a high affinity for pirenzepine (PZ), M, receptors, predominate in the hippocampus and cerebral cortex, whereas M2 receptors predominate in the cerebellum and brainstem, and M4 receptors are most abundant in the striatum. Central muscarinic and nicotinic receptors are targets of intense pharmacological interest for their potential roles in regulating abnormal neurological signaling in Alzheimer s disease, Parkinson s disease and certain seizure disorders. Nicotinic receptors are largely localized at prejunctional sites and control the release of neurotransmitters [10,11],... 

The central distribution of THC was studied in the primate brain using positron emission tomography (Charlambous et al. 1991). The THC analog, (-)-18F-A8-THC, was administered intravenously to baboons. Neuroanatomical distribution in the baboon brain was comparable to prior autoradiographic studies, with binding evident in the basal ganglia, thalamus, and cerebellum. Clearance was rapid from these areas. 

HT3 receptors are located exclusively on neurons and are widely distributed throughout the peripheral and central nervous systems. In the periphery, 5-HT3 receptors are found on autonomic, sensory, and enteric neurons (Fozard 1984). In the central nervous system, 5-HT3 receptors are labeled in cortex, hippocampus, caudate hypothalamus, brain stem, midbrain, and cerebellum, with the highest density in discrete nuclei of the lower brain stem (e.g., dorsal vagal complex and spinal trigeminal nucleus), the area postrema, and substantia gelatinosa at all levels of the spinal cord (Palacios et al. 1991 Waeber et al. 1989). 

The central nervous system consists of the brain and spinal cord. The average adult brain weighs 1250-1380 grams. The brain is divided into three gross parts the brainstem, the cerebrum, and the cerebellum. Structurally, the brain may be likened to a bouquet of flowers with the cerebrum (as two cerebral hemispheres) blossoming outwards above the brainstem the cerebellum is attached at the back of the brainstem. 

Figure 4.4 General structure of the brain the central nervous system consists of the spinal cord and the brain. The brain consists of the brain stem (medulla oblongata, cerebellum, pons, mesencephalon, diencephalon) and the cerebrum (cerebral hemispheres, subcortical white matter, basal ganglia).

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