TY - JOUR
T1 - The presence of serotonin (5-HT1) receptors negatively coupled to adenylate cyclase in rabbit and human iris-ciliary processes
AU - Barnett, Nigel L.
AU - Osborne, Neville N.
PY - 1993/1/1
Y1 - 1993/1/1
N2 - Serotonin (5-hydroxytryptamine, 5-HT) reduces forskolin-induced stimulation of cyclic AMP in rabbit iris-ciliary body (ICB) homogenates. The effect is dose dependent and can be mimicked by a number of 5-HT1 receptor agonists including 5-carboxamidotryptamine (5-CT) and RU 24969 [5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1-indole]. The inhibitory effects 5-CT and the 5-HT(1A) selective agent 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT) on forskolin stimulated adenylate cyclase activity are greater in isolated ciliary processes than in the iris musculature. Spiperone and propranolol significantly antagonize the action of 5-CT in the iris-ciliary body, while ketanserin (5-HT2 antagonist) and ICS 205930 (5-HT(3/4 blocker) were without influence, indicating the presence of the 5-HT(1A) subtype of receptor. Studies carried out on human ICB homogenates also suggest the presence of 5-HT(1A)-like receptors, although these receptors are not identical to those in rabbit. Similarities include dose-dependent decreases in cAMP levels stimulated by forskolin elicited by 1-(3-chlorophenyl) piperazine (mCPP), 5-CT and 8-OH-DPAT. Moreover, the inhibitory effect of 5-CT can also be significantly reduced by the 5-HT1 receptor antagonist, propranolol. However, unlike the case of rabbit tissue, spiperone was ineffective in abolishing the 5-CT response in human ICB homogenates.
AB - Serotonin (5-hydroxytryptamine, 5-HT) reduces forskolin-induced stimulation of cyclic AMP in rabbit iris-ciliary body (ICB) homogenates. The effect is dose dependent and can be mimicked by a number of 5-HT1 receptor agonists including 5-carboxamidotryptamine (5-CT) and RU 24969 [5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1-indole]. The inhibitory effects 5-CT and the 5-HT(1A) selective agent 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT) on forskolin stimulated adenylate cyclase activity are greater in isolated ciliary processes than in the iris musculature. Spiperone and propranolol significantly antagonize the action of 5-CT in the iris-ciliary body, while ketanserin (5-HT2 antagonist) and ICS 205930 (5-HT(3/4 blocker) were without influence, indicating the presence of the 5-HT(1A) subtype of receptor. Studies carried out on human ICB homogenates also suggest the presence of 5-HT(1A)-like receptors, although these receptors are not identical to those in rabbit. Similarities include dose-dependent decreases in cAMP levels stimulated by forskolin elicited by 1-(3-chlorophenyl) piperazine (mCPP), 5-CT and 8-OH-DPAT. Moreover, the inhibitory effect of 5-CT can also be significantly reduced by the 5-HT1 receptor antagonist, propranolol. However, unlike the case of rabbit tissue, spiperone was ineffective in abolishing the 5-CT response in human ICB homogenates.
UR - http://www.scopus.com/inward/record.url?scp=0027304897&partnerID=8YFLogxK
U2 - 10.1006/exer.1993.1116
DO - 10.1006/exer.1993.1116
M3 - Article
AN - SCOPUS:0027304897
SN - 0014-4835
VL - 57
SP - 209
EP - 216
JO - Experimental Eye Research
JF - Experimental Eye Research
IS - 2
ER -