Neurotransmitters Flashcards
characteristic sign for uncal herniation (shift in brain)
unresponsive pupil (to pupillary light reflex)
chemical released by cell (endocrine) that acts on neuron to alter its response to NT
neuromodulator (neuropeptides)
two general functions for chemical NT
rapid communication and neuromodulation (mediate synaptic transmission and neuronal growth)
most common excitatory NT, most common inhibitory
glutamate, GABA
most common NT in PNS at neuromuscular junction; what is most common for ANS?
Ach; norepinephrine
dopamine, norepi, epinephrine, serotonin are examples of this NT
monoamines
this NT thought to be involved in long term potentiation
glutamate
amino acid excitatory NT
aspartic acid and glutamic acid
inhibitory amino acid NT
GABA and glycine
indoleamine monoamine NT
serotonin
substance P, somatostatin, neurotensin, CCK, enkephalins/endoprhins are examples of this kind of NT
peptide
these are examples of putative NT
endogenous benzodiazepines and prostaglandin
this catalyzes acetylcholine
choline acetyltransferase
4 mechanisms for NT regulation of hypothalamic hormones
interneurons, direct, presynaptic, portal circulation
Ach functions mainly in neuromodulation…affects these functions
attention, memory, learning
major cholinergic pathways
pedunculopontine tegmental nuclei, septal nuclei, nucleus basalis of Meynert
major cholinergic pathway involved in arousal and coordinated locomotor activities
pedunculopontine tegmental nuclei to intralaminar thalamus
where is pedunculopontine tegmental nuclei cholinergic pathway located (*to intralaminar thalamus*)
lateral RF
cholinergic pathway that facilitates hippocampal theta rhythm related to memory
septal nuclei
cholinergic septal nuclei project here via fornix
hippocampus
where is nucleus basalis of Meynert?
substantia innominata
what is input to cholinergic nucleus basalis of Meynert? where does it project?
locus ceruleus, raphe nuclei, substantia nigra, amygdala, orbitofrontal cortex; cerebral cortex
cholinergic pathway that degenerates in Alzheimer’s disease
nucleus basalis of Meynert
lesion of central tegmental tract will cause this
coma
NT for VPLO hypothalamus
GABA
rate limiting step of catecholamine NT synthesis…present in all catecholamine neurons
tyrosine hydroxylase
all catecholamine NT are synthesized from this
tyrosine
septal nuclei projects via fornix to hippocampus/amygdala via this cholinergic pathway
diagonal band of broca
catecholamine dopamine can be identified by this marker
tyrosine hydroxyalse
this catecholamine is depleted in Parkinsons, increased in schizo.
dopamine
two MAJOR sources of dopamine in brain
substantia nigra pars compacta and VTA
dopaminergic pathway…SNc projects to striatum; dysfunction in this pathway causes what?
nigrostriatal pathway; Parkinson’s
dopaminergic pathway….from VTA to all cortical/subcortical structures of limbic system (*positive symptoms of schizo.*)
mesolimbic
where does dopaminergic mesolimbic pathway arise?
VTA
this drug blocks dopamine reuptake transporter
cocaine
these drugs are dopamine-releasing agents, also block reincorporation of dopamine into synaptic vesicles
amphetamine and meth
this drug attaches to specific excitatory receptors in plasma membrane of neuron
nicotine
drugs of abuse affect this dopamine pathway
VTA to nucleus accumbens
dopaminergic mesocortical pathway
VTA to prefrontal cortex
dopaminergic pathway involved in working memory, motor initiation; deficit produces what?
mesocortical pathway; hypokinesia and cognitive deficits (related to Parkinson’s)
major sources of serotonin
raphe nuclei and pineal gland
marker for catecholamine norepinephrine
dopamine B-hydroxylase
norepi is transmitter for these neurons
postgang. sympathetic
thalamus is inhibitory or excitatory to thalmus?
excitatory
these drugs can be used to treat epilepsy, anxiety, sedatives/anesthesia (*GABA agonist*)
benzodiazepenes (valium) and barbituates (pentobarbital)
two main areas for noradrenergic pathways
locus ceruleus and LTA
contains largest concentration of epinephrine in CNS (projects to ALL parts CNS)
locus ceruleus
inputs to noradrenergic locus ceruleus
cortex, limbic, RF, raphe nuclei, cerebellum, SC
NT from tuberomammillary nucleus
histamine
noradrenergic pathway/norepi store…significant loss in Alzheimer and Parkinson’s…plays role in *anxiety and panic disorders*
locus ceruleus
lateral tegmental area projects to hyopthalamus and thalamus via these pathways
central tegmental tract and MFB
noradrenergic located in medulla and pons…involved in sympathetic BP control (projects to hypothalamus and thalamus)
lateral tegmental area
marker for serotonin
tryptophan hydroxylase
plays important role in arousal, sensory perception, emotion, higher recognition…also depression, anxiety, OCD, aggression, eating disorders
serotonin
serotonin has these effects with low levels; this in high levels
depression and insomnia; mania
these can increase serotonin levels by blocking reuptake
tricyclic antidepressives
where do raphe nuclei project from the medulla, pons, and midbrain (serotonergic pathways)
spinal cord; cerebellum and SC; diencephalon and telencephalon
highest concentration of serotonin in body
pineal gland
pinealocytes convert serotonin to this
melanin
what endorphins are derived from
pro-opiomelanocortic (precursor to ACTH)
endorphins are found almost exclusively in these nuclei of the *hypothalamus*
arcuate and mammillary nuclei
where do endorphins in hypothalamus project to?
hypothalamus, amygdala, nucleus accumbens, septal area, thalamus, locus ceruleus
what are enkephalins derived from?
proenkephiln
most abundant and widely distributed opiod peptide
enkephalins
where are enkephalins in highest concentration? what circuit systems are they a part of?
globus pallidus; striatum and limbic
staining for GABA
glutamic acid decarboxylase
what does GABA coexist with mostly?
enkephalin and substance P
GABA-ergic neurons from striatal neurons project here
globus pallidus and substantia nigra
GABA-ergic neurons from pallidal and nigral neurons project here
thalamus
major inhibitory transmitter in SC; what blocks this inhibitory action?
glycine; strychnine
major excitatory NT in brain
glutamate
places that use glutamate NT
cerebellar granule, corticobulbar, corticospinal, DRG neurons
these glutamate receptors may be involved in long-term potentiation in the hippocampus
NMDA
this plays a role in kindling-induced seizures (and pain transmission of Ad and C fibers)
glutamate
glutamate is involved in these projections to globus pallidus
corticostriate and subthalamic
this NT is located in olfactory system, striatum, cortex, hippocampus, supraoptic nucleus and cerebellum
nitric oxide
ascending pathway of endogenous pain control involves this tract
spinoreticular (impulses to PAG)
descending raphespinal pathway for pain control
PAG-nucleus raphe magnus-serotonin to enkephalinergic interneurons dorsal horn (substantia gelatinosa)
this provides direct inhibition of tract cells hat give rise to ascending pain pathway
ceruleospinal pathway
these are present in Parkin’s disease in substantia nigra
Lewy bodies
Huntington disease has loss of these neurons in the striatum
Ach and GABA-ergic
these neurons are degenerated in nucleus basalis of Meynert in Alzheimer’s disease
cortical and cholinergic neurons
Alzheimer’s associated with a massive loss of this on cortex
Ach acetyltransferase
myasthenia gravis is characterized by antibodies to these
nicotinic Ach receptors (causes muscle paresis)
Lambert-Eaton myasthenic syndrome is caused by this; what does this cause?
presynaptic defect Ach release; limb weakness and autonomic dysfunction