<i>m</i>‐Octopamine: Normal Occurrence with <i>p</i>‐Octopamine in Mammalian Sympathetic Nerves

Ibrahim, Kamal E.; Couch, Margaret W.; Williams, Clyde M.; Fregly, Melvin J.; Midgley, John M.

doi:10.1111/j.1471-4159.1985.tb07180.x

Cited by 44 publications

(14 citation statements)

References 29 publications

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“…However, under conditions where MAO activity is inhibited TA levels can become significantly elevated displacing more efficacious 'true' neurotransmitters from their vesicles (Ibrahim et al, 1985). At even higher concentrations TAs enhance DA release, and to a lesser extent NE and 5-HT, into synapses.…”

Section: Biological Actions Of Trace Aminesmentioning

confidence: 99%

Trace amine-associated receptor 1—Family archetype or iconoclast?

Grandy

2007

Pharmacology & Therapeutics

176

211

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Interest has recently been rekindled in receptors that are activated by low molecular weight, noncatecholic, biogenic amines that are typically found as trace constituents of various vertebrate and invertebrate tissues and fluids. The timing of this resurgent focus on receptors activated by the 'trace amines' (TAs) β-phenylethylamine (PEA), tyramine (TYR), octopamine (OCT), synephrine (SYN), and tryptamine (TRYP) is the direct result of two publications that appeared in 2001 describing the cloning of a novel G protein-coupled receptor (GPCR) referred to by their discoverers as TA1 (Borowsky et al., 2001) and TAR1 (Bunzow et al., 2001). When heterologously expressed in Xenopus laevis oocytes and various eukaryotic cell lines recombinant rodent and human TA receptors dosedependently couple to the stimulation of cAMP production. Structure-activity profiling based on this functional response has revealed that in addition to the TAs, other biologically active compounds containing a 2 carbon aliphatic side chain linking an amino group to at least one benzene ring are potent and efficacious TA receptor agonists with amphetamine, methamphetamine, 3-iodothyronamine, thyronamine, and dopamine among the most notable. Almost 100 years after the search for TA receptors began numerous TA1/TAR1-related sequences, now called Trace AmineAssociated Receptors (TAARs), have been identified in the genome of every species of vertebrate examined to date. Consequently, even though heterologously expressed TAAR1 fits the pharmacological criteria established for a bona fide TA receptor a major challenge for those working in the field is to discern the in vivo pharmacology and physiology of each purported member of this extended family of GPCRs. Only then will it be possible to establish whether TAAR1 is the family archetype or an iconoclast.

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Section: Biological Actions Of Trace Aminesmentioning

confidence: 99%

Trace amine-associated receptor 1—Family archetype or iconoclast?

Grandy

2007

Pharmacology & Therapeutics

176

211

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“…Each isomeric form exists as D(-) and L(+) enantiomers. [50][51][52][53] However, the naturally occurring isomer of OCT is p-OCT in the octopus and other invertebrates, including insects, and is found in high concentration in the central nervous system, peripheral nervous system, and various other peripheral tissues. 8,54,55 The (-)-enantiomer of p-OCT is the naturally occurring form in honeybees.…”

Section: Isomersmentioning

confidence: 99%

Review of octopamine in insect nervous systems

Farooqui¹

2012

OAIP

147

155

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Octopamine (OCT) belongs to a group of compounds known as biogenic amines. OCT, a monohydroxylic analog of norepinephrine, is found in both vertebrate and invertebrate nervous systems. OCT is present in relatively high concentrations in the neuronal and nonneuronal tissues of most invertebrate species studied. However, OCT occurs as a trace amine in vertebrates where its physiological significance remains uncertain. OCT acts as a neurotransmitter, neuromodulator, and neurohormone in insect nervous systems where it prominently influences multiple physiological events. In the peripheral nervous system, OCT modulates the activity of flight muscles, peripheral organs, and most sense organs. In the central nervous system, OCT is essential for the regulation of motivation, desensitization of sensory inputs, arousal, initiation, and maintenance of various rhythmic behaviors, hygiene behavior, and complex social behaviors, including establishment of labor, as well as learning and memory. As a neurotransmitter, OCT regulates endocrine gland activity and controls the emission of light in the firefly lantern. As a neurohormone, OCT is released into hemolymph, transported to target tissues, and induces mobilization of lipids and carbohydrates, preparing insects for a period of extended activity or assisting recovery from a period of increased energy demand. OCT modulates hemocytic nodulation in nonimmune larvae and enhances phagocytosis as a neurohormone. OCT exerts its effects by binding to specific receptors belonging to the superfamily of G protein-coupled receptors and shares the structural motif of seven transmembrane domains. Activation of octopaminergic receptor types is coupled with different second messenger pathways depending on the species, tissue source, receptor type, and cell line used for expression of the cloned receptor. OCT-mediated generation of second messengers is associated with changes in cellular response, affecting insect behaviors. This review describes the roles of OCT in insect nervous systems at the behavioral and molecular levels.

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“…Introduction meta-Octopamine together with its positional isomer are now known to occur naturally in mammalian para-octopamine and their two N-methyl derivatives, tissues (Ibrahim et al, 1985). However, m-and pmeta-synephrine (phenylephrine) andpara-synephrine synephrine are found only in adrenal gland, whilst m-C The Macmillan Press Ltd 1988 and p-octopamine are found in several sympathetically innervated organs (heart, spleen, vas deferens, intestine, kidney, liver, lung, brain) and in adrenal medulla.…”

mentioning

confidence: 99%

Activities of octopamine and synephrine stereoisomers on α‐adrenoceptors

Brown¹,

McGrath

Midgley

et al. 1988

British J Pharmacology

100

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1 The activities of the (-)-and (+ )-forms of m-and p-octopamine and m-and p-synephrine on a,-adrenoceptors from rat aorta and anococcygeus and a2-adrenoceptors from rabbit saphenous vein were compared with those of noradrenaline (NA).2 The rank order of potency of the (-)-forms on cx,-adrenoceptors from rat aorta and a2-adrenoceptors was NA > m-octopamine = m-synephrine > p-octopamine = p-synephrine. The two m-compounds were 6 fold less active than NA on x,-adrenoceptors from rat aorta and 150 fold less active on x,-adrenoceptors. The two p-compounds were 1,000 fold less active than NA on both oqadrenoceptors from rat aorta and x2-adrenoceptors. The rank order ofpotency ofthe (-)-forms on oqadrenoceptors from rat anococcygeus was NA = m-synephrine > m-octopamine >p-octopamine = p-synephrine. m-Octopamine was 4 fold less active than NA and (-)-m-synephrine. The two pcompounds were 30 fold less active than NA. 3 The rank order of potency of the (+)-forms was NA>m-octopamine>m-synephrine>p-octopamine >p-synephrine on both a,-and M2-adrenoceptors. The potency ofeach ( + )-form was 1-2 orders of magnitude less than that of the (-) counterpart, the differences being greater for the stereoisomers of synephrine than for those of octopamine on both a,-and M2-adrenoceptors. 4 The yohimbine diastereoisomer antagonists, rauwolscine and corynanthine, were tested against (-)-NA and (-)-m-octopamine-induced contractions in both preparations. Based upon the known selectivities of these isomers for a-adrenoceptor subtypes, it is concluded that the rat aorta contains only a,-adrenoceptors while the rabbit saphenous vein possesses predominantly M2-adrenoceptors.5 Ligand binding data for the octopamine and synephrine stereoisomers at oq-and a2-binding sites from rat cerebral cortex was also obtained. (-)-Forms were more active than (+ )-forms. The rank order of affinity of the (-)-forms for both a,-and M2-binding sites was NA > m-octopamine = msynephrine >p-synephrine >p-octopamine. The relative affinities ofthe members ofthe series against a,-binding sites were very similar to their relative functional activities on rat aorta. However, the affinities of both m-and p-compounds relative to that of ( -)-NA were much greater at the x2-binding sites than were the relative activities in rabbit saphenous vein, possibly suggesting low intrinsic efficacy. Functional antagonist responses to NA by the (-)-octopamine and synephrines could not, however, be demonstrated on rat aorta or rabbit saphenous vein. 6 The activities of m-octopamine and m-synephrine were not significantly different from each other on either a,-adrenoceptors from rat aorta or x2-adrenoceptors; however, m-synephrine is more active than m-octopamine on a,-adrenoceptors from rat anococcygeus. Both m-octopamine and msynephrine can be considered to be naturally occurring x,-selective amines. However, if m-and poctopamine are co-released with NA in amounts proportional to their concentration, it is concluded that their activities on m,-and x2-adrenoceptors are too low to be ...

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m‐Octopamine: Normal Occurrence with p‐Octopamine in Mammalian Sympathetic Nerves

Cited by 44 publications

References 29 publications

Trace amine-associated receptor 1—Family archetype or iconoclast?

Trace amine-associated receptor 1—Family archetype or iconoclast?

Review of octopamine in insect nervous systems

Activities of octopamine and synephrine stereoisomers on α‐adrenoceptors

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