Figure 14.

Intravenous administration of 5-hydroxytryptamine (5HT) 2A agonist (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) elicits ear pinna cutaneous vasoconstriction. (A) The 5HT2A agonist DOI (100 µg/kg i.v.) decreases Doppler blood flow signal selectively in ear pinna not in mesenteric artery, and increases body temperature in a conscious rabbit. Modified from Blessing and Seaman.¹⁰⁷ © Elsevier. Permission to reuse must be obtained from the rightsholder. (B) Microinjection of muscimol into the medullary raphé (1 nmol in 100 nl) inhibits spontaneous cutaneous sympathetic activity in ear pinna in an anesthetized rabbit. Subsequent DOI (0.1 mg/kg, i.v.) administration activates ear pinna sympathetic fiber. The circled numbers (1-3) on the nerve discharge traces correspond to the circled numbers on the X axis in the integrated nerve activity traces, indicating the experimental period during which the nerve recording was made. Modified Ootsuka et al.¹⁰⁶© Elsevier. Permission to reuse must be obtained from the rightsholder.