TY - JOUR
T1 - The effect of serotonin on the rabbit isolated iris sphincter muscle
AU - Barnett, Nigel L.
AU - Osborne, Neville N.
PY - 1993/1/1
Y1 - 1993/1/1
N2 - The rabbit isolated iris sphincter muscle maintained in an isotonic state is unaffected by applied serotonin (5-hydroxytryptamine or 5-HT) whereas carbachol causes the muscle to contract. Serotonin does, however, produce a relaxation of the contracted muscle in a dose-dependent manner. This effect is also induced by the 5-HT receptor agonists 8-OH-DPAT (8-hydroxy-2-[di-n-propyl-amino] tetralin, RU 24969 (5-methoxy-3-[l, 2, 3, 6, tetrahydro-4-pyridinyl]-1-indole) and ipsapirone, suggesting the involvement of 5-HT1A receptors. This view is supported by the finding that metergoline, methysergide and propranolol all counteracted the effect produced by serotonin. While 5-HT3 receptors are not involved in the described process, a minor involvement of 5-HT2 receptors cannot be excluded as methysergide partially counteracted the serotonin response. These data provide evidence that serotonin receptors, in particular the 5-HT1A subtype, may be associated with the iris sphincter muscle and suggest their involvement in the regulation of pupil size.
AB - The rabbit isolated iris sphincter muscle maintained in an isotonic state is unaffected by applied serotonin (5-hydroxytryptamine or 5-HT) whereas carbachol causes the muscle to contract. Serotonin does, however, produce a relaxation of the contracted muscle in a dose-dependent manner. This effect is also induced by the 5-HT receptor agonists 8-OH-DPAT (8-hydroxy-2-[di-n-propyl-amino] tetralin, RU 24969 (5-methoxy-3-[l, 2, 3, 6, tetrahydro-4-pyridinyl]-1-indole) and ipsapirone, suggesting the involvement of 5-HT1A receptors. This view is supported by the finding that metergoline, methysergide and propranolol all counteracted the effect produced by serotonin. While 5-HT3 receptors are not involved in the described process, a minor involvement of 5-HT2 receptors cannot be excluded as methysergide partially counteracted the serotonin response. These data provide evidence that serotonin receptors, in particular the 5-HT1A subtype, may be associated with the iris sphincter muscle and suggest their involvement in the regulation of pupil size.
UR - http://www.scopus.com/inward/record.url?scp=0027237174&partnerID=8YFLogxK
U2 - 10.3109/02713689309001846
DO - 10.3109/02713689309001846
M3 - Article
C2 - 8222726
AN - SCOPUS:0027237174
SN - 0271-3683
VL - 12
SP - 665
EP - 673
JO - Current Eye Research
JF - Current Eye Research
IS - 7
ER -