TABLE 2. Known biochemical and pharmacological differences between primate and rodent catecholamine neurons a,b

Characteristic

Rodent

Primate

References

Tyrosine hydroxylase (mRNA transcripts)

Single

Multiple

(32)

Monoamine oxidase

(relative abundance in striatum)

Type A > Type B

Type B > Type A

(45)

Dopamine metabolism (major end metabolites)

DOPAC + HVA

HVA

(3)

Norepinephrine metabolism (major end metabolites)

DHPG + MHPG

sulfates

MHPG

(24)

Phenolsulfotransferase (affinity for DA and NE)

Low

High

(54)

Phenolsultotransferase (affinity for deaminated and

O-methylated DA and NE metabolites)

High

Low

(54)

Adenylate cyclase (efficacy of partial D1 agonist to

stimulate)

High

Low

(48) (but see ref. 67)

Neurotensin colocalization (in DA neurons)

Present

Low

(7),(9),(56)

CCK colocalization (in mesocortical DA neurons)

Present

Low

(55),(56)

Susceptibility to MPTP (nigrostriatal DA toxicity)

Low

High

(23)

D1/D2 receptor interaction

Established

Uncertain

(65)

a Some differences in the biochemical pharmacology of central catecholamine neurons between the rodent and primate. In addition, the amino acid sequence of transporter proteins and some of the metabolic enzymes are different between the species, although these have not been related to functional differences.

b Abbreviations: DA, dopamine; NE, norepinephrine; HVA, homovanillic acid; DOPAC, dihydroxyphenyl-acetic acid; MHPG, 3-methoxy-4-hydroxyphenylglycol; DHPG, 3,4-dihydroxyphenylglycol.
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published 2000