Sedative: Antispacity drugs and Muscle relaxants 1

Blood brain barrier (BBB)

Selective filtration of the CNS capillaries via tight junctions between capillary endothelial cells

Passive diffusion

nonpolar, lipid-soluble drugs

Carrier-mediated transport

polar and lipophobic compunds

• facilitated diffusion

• endocytosis

• active transport

Acetylcholine

CNS Neurotransmitters: Excitation

• cerebral cortex

• basal ganglia

• limbic and thalamic regions; spinal interneurons

Norepinephrine

CNS Neurotransmitters: Inhibition

• neurons originating in brainstem and hypothalamus that project throughout other areas of the brain

Dopamine

CNS Neurotransmitters: Inhibition

• basal ganglia

• limbic system

Serotonin

CNS Neurotransmitters: Inhibition

• Neurons originating in brainstem that project upward (to hypothalamus) and downward (to spinal cord)

GABA

CNS Neurotransmitters: Inhibition

• interneurons in:

  • spinal cord

  • cerebellum

  • basal ganglia

  • cerebral cortex

Glycine

CNS Neurotransmitters: Inhibition

• interneurons in spinal cord and brainstem

Glutamate, Aspartate

CNS Neurotransmitters: Excitation

• Interneurons throughout brain and spinal cord

Substance P

CNS Neurotransmitters: Excitation

• pathways in spinal cord and brain that mediate painful stimuli

Enkephalins

CNS Neurotransmitters: Excitation

• pain suppression pathways in spinal cord and brain

Presynaptic inhibition

Action potential are blocked propagating to the presynaptic terminal. Thus no release of neurotransmitters or activity occurs in the synaptic cleft.

• e.g. GABA (inhibitory neurotransmitters)